-general cleanup

 - fixes #2542

Allows QGC to run on Raspberry Pi 2 with direct framebuffer (X/startx
not needed). Memory split seems to need 128 for GPU. Qt5 needs to be
configured with "-opengl es2 -qpa eglfs -device linux-rasp-pi2-g++".

Revert "Update NSIS script to include ANGLE dlls for windows, add NSIS script to otherfiles on windows"

This partially reverts commit 233ea3b4.

Also removed a redundant DLL (OpenGL was being copied twice).

- All resources are either under src or under resources dirs
- Removed files top level directory
- Move flightgear files to top level dir

Also added more plugins, just in case

Allows parameter access from QML among other things

And I really mean it this time!

Copy platforms plugins to install

Revised the DLLs that are copied post-compilation so that QGC.exe can run.
Improved robustness by quoting all filenames/paths.

Files were not being copied to correct location