Unity Sprite Atlas Compression

http://forum.unity3d.com/threads/2d-sprite-packer-and-pvrtc.218633/

http://docs.unity3d.com/Manual/SpritePacker.html

http://docs.unity3d.com/Manual/class-TextureImporter.html

http://docs.unity3d.com/ScriptReference/Sprites.AtlasSettings-compressionQuality.html

http://docs.unity3d.com/ScriptReference/Sprites.AtlasSettings.html