Clean up project structure

Created by: LNJ2

I have to say I don't like the structure as it is, now. The app folder is unnecessary, because everything else should probably also belong to app. And I also don't like it to first have to cd app/ and only do qmake ; make, instead of directly do qmake ; make.

However I would suggest this structure:

• bin - Binaries (should be created after building)
• doc - Documentation / Licenses
  • license_gpl-3.0.txt
  • license_cc_by-sa-4.0.txt
• src - Source Code
  • qml QML-files
    • *.qml
  • *.cpp *.h
• data
  • images
    • *.png *.svg
  • sounds
    • *.opus *.flac
  • fonts
    • *.ttf
• util - Utilities (travis-ci scripts, deb/rpm package files, ...)
• misc - Miscellaneous (for logos, .desktop-files, ...)
• README.md
• LICENSE.txt
• kaidan.pro
• kaidan.qrc
• deployment.pri

I also like this structure, but I think the one above might be better for our project.

What do you think about this?