Squashed commit of the following:

commit ab51a01b
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Fri Nov 7 20:46:35 2014 +0100

    Only show error dialog when outside the dashboard.

commit 1ef5e62b
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Fri Nov 7 12:28:36 2014 +0100

    Fix issues pointed out in review.

commit a8e645a5
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Fri Nov 7 01:27:07 2014 +0100

    Clean up #includes in collection.cpp

commit 27ca1927
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Fri Nov 7 01:22:14 2014 +0100

    Don't show the selection dialog for practice when showing due words in the dashboard.

commit 3b776d2b
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Fri Nov 7 01:16:54 2014 +0100

    Collect the number of words due for every collection in the dashboard.

commit 28cd6d60
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Thu Nov 6 23:47:52 2014 +0100

    Make the "x words due" feature work

commit 25761b00
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Wed Nov 5 01:57:57 2014 +0100

    Clean up the collection widget

    Also collect things to do for this branch in the TODO file.

commit f57e5bc2
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Wed Nov 5 01:22:44 2014 +0100

    Connect the collection widget to the collection.

commit ef73d47d
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Tue Nov 4 18:38:44 2014 +0100

    More preparations for starting to use the Collection class.

    This time it's mostly refactoring in the collection widget.

commit 29c4f609
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Tue Nov 4 02:28:56 2014 +0100

    Prepare the collection class for inclusion into the rest of Parley

commit 37fb8593
Merge: 7cf9b768 ab85a8b2
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Mon Nov 3 15:26:03 2014 +0100

    Merge branch 'KDE/4.14' into collection-class

commit 7cf9b768
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Sat Nov 1 01:36:35 2014 +0100

    Forgot to commit this

commit 8fd22184
Author: Inge Wallin <inge@lysator.liu.se>
Date:   Sat Nov 1 01:12:40 2014 +0100

    First draft of the new collection class.