[BlackBerry10] Add support for BB10 platform

This uses the exec proxy to wrap functionality from com.blackberry.push.

Documentation available here:
http://developer.blackberry.com/html5/documentation/v2_1/push_service.html
rollback and fix to support both iOS 8 and iOS < 8, on Xcode 6 & before
add support for iOS 7
fix for compiling in Xcode 5
[2.4.0] upped version
Merge remote-tracking branch 'upstream/master'