Updates from Mon 30 Mar

- [ReactNative] Clean up no longer needed reference to NavigationBarClass | Philipp von Weitershausen
- [TextInput] returnKeyType, enablesReturnKeyAutomatically, secureTextEntry, more keyboardTypes | Tadeu Zagallo
- [ReactNative] PropTypes for NavigationBars | Philipp von Weitershausen
- Changed LayoutAnimation to use ms instead of seconds for consistency | Nick Lockwood
- Better date support | Nick Lockwood
- Renamed throttleScrollCallbackMS to scrollEventThrottle | Nick Lockwood
- Fixed threading issues in RCTImageDownloader | Nick Lockwood
- [iOS][Assets]: Cleaning up more 1x png from Libraries | Radu Marin
- [ReactNative][docs] LinkingIOS | Tadeu Zagallo
- Fixing TouchableOpacity and TouchableHighlight documentation | Ben Alpert
- [react-native] Add React.addons.createFragment | Ben Alpert