Merge pull request #203 from superandrew213/fix-uimanager

Use UIManager.getViewManagerConfig

src/GLCanvas.captureFrame.android.js

 import invariant from "invariant";
 import {NativeModules} from "react-native";
 const {UIManager} = NativeModules;
-const {GLCanvas} = UIManager;
+const GLCanvas = UIManager.getViewManagerConfig('GLCanvas');
 invariant(GLCanvas,
 `gl-react-native: the native module is not available.
 Make sure you have properly configured it.