Add removeObjectForKey method to IASKSettingsStore protocol.
Also implement this method in File and UserDefaults Settings store.
Updated README: IASK is now ARC-enabled
Improved subclassing of IASKAppSettingsViewController

by not removing all notification observers but just the ones we added
Merge pull request #225 from olicarbo/upstream

Add removeObjectForKey method to IASKSettingsStore protocol.
Ignore .xcuserdata
silence compiler warnings when implementing custom settings store (by @mman)
Fixed removal of NSUserDefaultsDidChangeNotification

close #234
Sample App: iOS 7 modifications

close #224
Support ShortTitles for Multi Value Elements (introduced in IOS 5.0)

thx @meizy
Fixed warnings and modernized build settings
Merge commit '7e5ae5db8e10a02ad9cd6324c093fef400d2b5f5'