Fullscreen effects always need to be in sRGB. close RobertBeckebans#292

Updated release notes

ATI hotfix for shadow mapping. RobertBeckebans#116

Disabled MSAA 16x option which is a performance killer in combination…

… with shadow mapping

Reduced FFmpeg debug console prints

Shadow LOD fix for parallel lights

Added support for loading .png image files as textures and changed sc…

…reenshot command to write in .png format