FlxSprite: consistent naming for the "load-graphic"-functions

loadFromSprite() -> loadGraphicFromSprite()
loadImageFromTexture() -> loadGraphicFromTexture()
loadRotatedImageFromTexture() -> loadRotatedGraphicFromTexture()
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into spriteGraphic

Conflicts:
	flixel/FlxSprite.hx
Fix copy paste error
Merge pull request #845 from Gama11/spriteGraphic

FlxSprite: consistent naming for the "load-graphic"-functions