iOS 7 add library support

[toddwong]

Do not change the deployment target of the Xcode project, but weak link the framework (marked as Optional).

See git@github.com:quellish/Weakness.git

[ligaz]

Hey @toddwong

Thanks for you suggestion. We are planning on adding static lib support for plugins and library add. See #685

[toddwong]

OK