add file sharing vie Vkontekte service
Dropbox feature and submodule dropbox-sdk-ios were added to ShareKit
BUGFIX: #662 - better Facebook error handling
Merge pull request #674 from ankstoo/master

Add file sharing for Vkontakte service
BUGFIX: VKontakte share now calls sendDidStart (and shows activity indicator)
Merge branch 'master' of github.com:VNikitin/ShareKit into Dropbox

Conflicts:
	Classes/ShareKit/ShareKit.bundle/en.lproj/Localizable.strings
BUGFIX: localised name for Dropbox
SUBMODULE UPDATE: Dropbox SDK
BUGFIX: Plurk did not compile if SHKDebug was on
Google Plus SDK as separate target
Facebook iOS sdk target separated