graphicsframework

* Added checks for availability of windowed/fullscreen mode
* Initial windowed mode is now set to 1024x768
* Fullscreen always uses full desktop resolution
* Windowed dimensions are preserved and restored when returning from fullscreen
* toggleFullscreen() now uses SDL_SetVideoMode() as SDL_WM_ToggleFullScreen is not supported on all platforms!
* WindowManager::initialize() now accepts video mode parameters

Fixed:
Window is initialized in windowed mode and only after that set to fullscreen if requested.
This fixes 100% CPU bug, although it#s still unknown why...

Current CPU consumption: 2-5% :-)