MapView to support MKPointAnnotation using new attribute annotate in Map...

Summary:
### MapView to support Pin annotation

    var pinLocation = {
			latitude: property.latitude,
			longitude: property.longitude,
			title: property.title
    };
    this.state = {propertyPoint: pinLocation};
    <MapView style={styles.map} region={this.state.region} annotate={this.state.propertyPoint}>
    </MapView>
![mapview-pinannotation](https://cloud.githubusercontent.com/assets/845379/7100280/6c1ffc08-dfe5-11e4-9d1b-8da6a65da1bc.png)

Closes https://github.com/facebook/react-native/pull/810
Github Author: guru inamdar <guru.inamdar@gmail.com>

Test Plan: Imported from GitHub, without a `Test Plan:` line.

Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js

@@ -7,7 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule loadSourceMap
- * @flow
+ * -- disabled flow due to mysterious validation errors --
  */
 
 'use strict';