Squashed commit of the following:

commit a90fb13b
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Sep 10 22:13:45 2017 +0800

    Fix build outside of Windows again

commit 950ef85b
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Sep 10 22:04:22 2017 +0800

    Fix build outside of Windows

commit 932a2515
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Sep 10 21:51:23 2017 +0800

    Enable ANGLE and add config options (Windows)

commit 1808e90e
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Sep 10 01:58:41 2017 +0800

    Add additional Windows OpenGL checking

commit bc059b74
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sat Sep 9 22:10:33 2017 +0800

    Refactor OpenGL checking code

commit 58033f21
Merge: 0ee46367 91be0979
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Fri Sep 8 22:51:44 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 0ee46367
Author: Boudewijn Rempt <boud@valdyas.org>
Date:   Thu Aug 24 15:11:20 2017 +0200

    Fix check for opengl

commit a3e07836
Merge: ba26bfb3 6ddc5109
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sat Aug 19 17:57:06 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit ba26bfb3
Merge: b761e0ec cb324d59
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 20:57:04 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit b761e0ec
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 20:23:44 2017 +0800

    Add comment explaining OpenGLES-specific code

commit 81687795
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 19:23:31 2017 +0800

    Add call to GL_BLEND after use

commit d3056322
Merge: f89ad0a2 dbbbb67f
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 19:21:03 2017 +0800

    Merge branch 'alvin/logging-capture' into alvin/T6696-opengl-angle

commit dbbbb67f
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 19:09:31 2017 +0800

    Change foreach to Q_FOREACH

commit f89ad0a2
Merge: 8133eb46 19de1d3f
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 00:54:19 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 8133eb46
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 00:41:53 2017 +0800

    Force ANGLE to use D3D11

    We need OpenGL ES 3 so D3D9 is unsupported. WARP weirdly get crashes on
    my environment so it'll be disabled for now until we decide to update
    the version of ANGLE used with Qt 5.9.x.

    Maniphest Tasks: T6696

commit 6f0b9df3
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 15 00:23:10 2017 +0800

    Add log capturing of QPA OpenGL check for diag on Windows

    We want to log the checking done by the OpenGL testing, buglist
    application, and the GpuDescription detail for adding to buglist if
    needed. The captured log is also available in the system info dialog.

    Maniphest Tasks: T6760, T6696

commit 56647b4f
Merge: e3b45ab7 9ae556ff
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Aug 14 03:03:28 2017 +0800

    Merge branch 'alvin/logging-capture' into alvin/T6696-opengl-angle

commit 9ae556ff
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Aug 14 00:57:08 2017 +0800

    Add missing license headers

commit e3b45ab7
Merge: fda0af0e 26e43cd8
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Aug 14 00:45:12 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 278cc34f
Merge: 221f6415 26e43cd8
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Aug 14 00:36:12 2017 +0800

    Merge branch 'master' into alvin/logging-capture

commit 221f6415
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Aug 14 00:11:15 2017 +0800

    Add KisLoggingManager for capturing log messages

    This class is mainly for capturing log messages from the Qt logging
    infrastructure (QLoggingCategory and qDebug etc.) for providing
    diagnostics information for use in bug report and showing them in the UI
    for convenience. For its limited use at the moment, this class is not
    made to be thread-safe in any sense.

    It can be extended in the future for more use, though it should be made
    thread-safe for any more complex tasks.

commit fda0af0e
Merge: 8a3f6805 2d1edd4e
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Fri Aug 11 23:13:21 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 8a3f6805
Merge: 6f077eed 281c44b3
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Fri Aug 11 03:10:12 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 6f077eed
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Fri Aug 11 03:03:29 2017 +0800

    Add texture format fallback for OpenGL ES 3

    This uses texture swizzle mask to swap the red and blue channels if the
    implementation does not support GL_EXT_texture_format_BGRA8888.

commit 8c2d0478
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Thu Aug 10 01:02:25 2017 +0800

    Change texture formats used with OpenGL ES 3

    This removes the use of certain formats that could crash when OpenEXR is
    not present. The modified code also does not work with OpenGL ES 3
    implementations without GL_EXT_texture_format_BGRA8888 support with
    certain image formats. Instead, a safe assert will trigger and the image
    will be rendered with the red and blue channels swapped.

    Maniphest Tasks: T6696

commit 1452ed52
Merge: 7be63a5b dc6cd471
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Wed Aug 9 16:39:17 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 7be63a5b
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Aug 6 22:33:21 2017 +0800

    Enable qt.qpa.gl logging on Windows

    Maniphest Tasks: T6696

commit 82ef9261
Merge: 5a6dd916 30353b4d
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sun Aug 6 00:49:08 2017 +0800

    Merge branch 'master' into alvin/T6696-opengl-angle

commit 5a6dd916
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Sat Aug 5 04:25:58 2017 +0800

    Use blending to paint brush outline on OpenGL ES 3

    Maniphest Tasks: T6696

commit 63ceca75
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Thu Aug 3 23:04:13 2017 +0800

    Call QSurfaceFormat::setDefaultFormat only once

    In theory, as long as it's set before QApplication is created and not
    changed after that there should be no problem. However Qt outputs a
    warning even if it's called with the same arguments. We should reduce
    logging noise.

commit c8b2d7a2
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Thu Aug 3 12:00:09 2017 +0800

    Patch Qt for building ANGLE with mingw-w64 7.1 and Windows 10 SDK

    Maniphest Tasks: T6696

commit f7a46a46
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 1 21:44:45 2017 +0800

    Patch Qt qopengldebug.cpp to fix crash with ANGLE

    Maniphest Tasks: T6696

commit 5b2cc36b
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Wed Aug 2 16:41:29 2017 +0800

    Use texture formats supported by OpenGL ES 3

    Maniphest Tasks: T6696

commit d7180793
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 1 03:41:22 2017 +0800

    Disable unsupported functions on OpenGL ES 3

    Maniphest Tasks: T6696

commit a19df1a8
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Tue Aug 1 01:21:02 2017 +0800

    Support OpenGL ES 3 shaders

    Maniphest Tasks: T6696

commit f8585d24
Author: Alvin Wong <alvinhochun@gmail.com>
Date:   Mon Jul 31 02:04:51 2017 +0800

    Enable dynamic OpenGL for Windows Qt and build ANGLE

    Maniphest Tasks: T6696