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
REFACTORING: Google+ uses native share dialogue instead of a trip to browser.

- removed GTL project. Files needed in Google+ and YouTube sharers are supplied via precompiled GoogleOpenSource.framework instead
- added GoogleOpenSource.framework to Frameworks
- added GooglePlus.bundle to Frameworks
NEW FEATURE: google+ image and video share
COCOAPODS: updated podspec 2.5.0
BUGFIX: fixed few warnings
SERVICE UPDATE: Google+ 1.5.0
PODSPEC: 2.5.1 update
BUGFIX: fixed warnings in the demo project
BUGFIX: No delegate callback after Google+ share
fixed crash with SHKForkController predicate in twitter sharing
Merge pull request #833 from K-Be/master

fixed crash with SHKFormController predicate in twitter sharing
FRAMEWORK UPDATE: Facebook iOS sdk 3.11
PODSPEC UPDATE: raised minimal iOS version due to 64 bit compatibility
DEMO APP NEW FEATURE: added large video example share option
NEW FEATURE: SHKDropbox can get user info
BUGFIX: localization typo, fixes #844
NEW FEATURE: SHKDropbox user can select target folder