made the static reference to the current view controller 'weak'
doing more cleanup in SPViewController
removed 'isa' usage (deprecated in iOS 7)
small code readability change
fixed unit test for Xcode 5
changed method implementation to avoid warning in Xcode 5
changed enum type to avoid warning in Xcode 5
project update (Xcode 5)
added 'xcshareddata' to git ignore file (Xcode 5)