Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
added sprite kit button/control plugin nodes
pbxproj update with button/control plugin nodes
Abstract PlugIn nodes no longer dealloc immediately

Under MRC they must have remained in memory but were inaccessible. I decided to store them in a separate dictionary just to prevent any odd issues due to abstract "base" plugins deallocating.
pbxproj with icon fixes for SBButton plugin

also prevents SBButton plugin from occasionally not appearing at all (and removing all button instances from the ccb because of it)
disable physics tab for sprite kit
sb+sk submodule ref
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
sb+sk submodule ref
change color sprite icons
updated default SK project
gitignore: ignore published ccbResources in default SK project
Merge pull request #321 from KoboldKit/develop-steffen

button node + sb plugin