NEW FEATURE: Pinterest sharer Fixes #837
BUGFIX: URLPictureURI image is shown even for SHKShareTypeText
Merge branch 'master' into pinterest

* master:
  BUGFIX: URLPictureURI image is shown even for SHKShareTypeText
  NEW FEATURE: URL share now asynchronously downloads and displays thumbnail image of item.URLPictureURI or item.URL itself. The latter if SHKURLContentTypeImage is set. Fixes #867
  BUGFIX: added alert if user wants to share on iOS sharer but disallowed access in Settings. Fixes #915
  BUGFIX: update already saved NSUserDefaults favourite sharers key with new SHKiOSTwitter or SHKiOSFacebook sharers. Fixes #885
  BUGFIX: Doc change - Facebook app id is required also in iOS sharer. Fixes #914

Conflicts:
	ShareKit.xcodeproj/project.pbxproj