[gif] - use shared_ptr for preventing excessive copy of GifFrames during extraction
[Gif] - remove unneeded code
[Gif] - remove tabs
[guitexture/anim] - only update framestate when lasttime is set
[GUITexture] - factor the reset of animation state members out into method resetAnimState
[Gif] - make GifFrame copy c'tor private (keep the code in case we need it at some point)