[attributedlabel] Add support for text shadows.

Closes #206.
[attributedlabel] Use the correct shadow color properties.
Merge branch 'master' into arc

Conflicts:
	src/attributedlabel/src/NIAttributedLabel.m
[attributedlabel] Remove lineBreakMode assertions. Document the differences between UILabel and NIAttributedLabel's treatment of lineBreakMode.
Merge branch 'master' into arc
Merge branch 'arc'
Updates for iOS 6.
Update JSONKit commit to latest master.
Add Nimbus icons and default images for iPhone.
[webcontroller] Point to the correct docs location.
Add the Nimbus icons to each sample project.
[core] Flesh out the core docs. Add more autoresizing masks.
Remove redundant docs.
Remove dead link.
Remove more dead links.
Fix broken links in release docs.
[core] Get unit tests building again on Xcode 4.5.
[core] Add removeAllObjectsWithPrefix: method to the in memory cache.
[core] Fix compiler warnings in the core addition tests.
Don't generate coverage stats until we get this working in Xcode 4.5 again.