add sprite kit texture atlas script to pbxproj
sk texture atlas gen minro changes
Publisher: SK spritesheet check tool exists, additional warnings/errors
pbxproj: remove texture atlas script, added txt file with location to texture atlas tool
pbxproj: changed the target for the texture atlas tool .txt file
Publisher: cleanup
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
SB: publisher exports spriteFrame property first (Sprite Kit exports only)
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
update SB+SK submodule ref
Merge pull request #299 from KoboldKit/develop-steffen

SK Texture Atlas generation finished