citra: Remove GLFW, Add SDL2
FindSDL2: Do not CACHE SDL2_* variables if library is not found
EmuWindow_SDL2: Set minimal client area at initialisation time
EmuWindow_SDL2: Corrections
EmuWindow_SDL2: Fix no decorations on startup on OS X
cmake: windows_copy_files
Several cleanups to the buildsystem:
- Do better factoring of common libs between platforms.
- Add support to building on Windows.
- Remove Qt4 support.
- Re-sort file lists and add missing headers.
This should fix the GL loading errors that occur in some drivers due to
the use of deprecated functions by GLEW. Side benefits are more accurate
auto-completion (deprecated function and symbols don't exist) and faster
pointer loading (less entrypoints to load). In addition it removes an
external library depency, simplifying the build system a bit and
eliminating one set of binary libraries for Windows.
MerryMage