SB ARC: fix LabelTTF node not showing the system font list
refactor: replaced appdelegate singleton properties (resource, plugin)

- prevent confusing them as properties/ivars of the appdelegate
- use the singletons the same way throughout app (some code went through appdelegate properties, most used sharedManager singleton accessor as one would expect it to be used)
- removed passing around resource manager to another class (one instance)
SB ARC: fix wrong and superfluous uses of weak/__weak
Merge branch 'refs/heads/develop' into convert-reader-to-SK
fix wording on color node descriptions
SK reader reads labels
CCBReader: test (string.length > 0) instead of slower (string isEqualToString:@"")
SK reader: fix color issues, read emitter node (wip)
SK reader: read label, emitter, refactored CCColor with NSCopying, description