fix up compile warning.
Merge pull request #275 from jtwigg/develop

fix up compile warning.
Fixes issue with disappearing icons
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop
pin joint rendering on screen.
Merge branch 'develop' of https://github.com/apportable/SpriteBuilder into chipmunk

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
fix expander.
improve hit test of joints.
working selection, deselections.
Fix observers for Pivots.
Add scene graph instead of Globals.
body nodes can be relocated.
readonly textfield
if physics is disabled, fixup references.
working hidden and visible buttons.
disable physics editor if Join.