Enabled textAlign in TextInput

Summary:
Added remapping of style textAlign property to textAlignment (which is the name of the same property on text input components)
Closes https://github.com/facebook/react-native/pull/772
Github Author: Daryl Rowland <daryl@cloudyclear.com>

Test Plan: Not sure. I tried cleaned and rebuilt and my TextInput works, though! Do we need to set up any unit tests or examples for this?

React/Views/RCTTextFieldManager.m

@@ -39,6 +39,7 @@ RCT_EXPORT_VIEW_PROPERTY(secureTextEntry, BOOL)
 RCT_REMAP_VIEW_PROPERTY(password, secureTextEntry, BOOL) // backwards compatibility
 RCT_REMAP_VIEW_PROPERTY(color, textColor, UIColor)
 RCT_REMAP_VIEW_PROPERTY(autoCapitalize, autocapitalizationType, UITextAutocapitalizationType)
+RCT_REMAP_VIEW_PROPERTY(textAlign, textAlignment, NSTextAlignment)
 RCT_CUSTOM_VIEW_PROPERTY(fontSize, CGFloat, RCTTextField)
 {
   view.font = [RCTConvert UIFont:view.font withSize:json ?: @(defaultView.font.pointSize)];