Fixed crash iOS 6 native twitter authorization
Merge pull request #825 from tkach/master

Fixed crash in iOS 6 native twitter authorization
BUGFIX: iOS sharer native iOS UI can not fetch user info - now the sharer does not try to use SLComposeViewController for this.
BUGFIX: demo app accounts view now shows only sharers who can share, and require authorisation
DOCUMENTATION: updated sharer matrix
Merge branch 'master' of github.com:ShareKit/ShareKit
BUGFIX: Google+ now has authorisation methods working. You can authorise/deauthorize the user as in other sharers. Fixes #709