Improvements on documentation (#340)

* Improvements on documentation and some refactor

* ts | js -> typescript (docs)

src/plugins/camera.ts

@@ -93,14 +93,16 @@ export interface CameraPopoverOptions {
  * Requires {@link module:driftyco/ionic-native} and the Cordova plugin: `cordova-plugin-camera`. For more info, please see the [Cordova Camera Plugin Docs](https://github.com/apache/cordova-plugin-camera).
  *
  * @usage
- * ```js
- * import {Camera} from 'ionic-native';
+ * ```typescript
+ * import { Camera } from 'ionic-native';
+ *
  *
  * Camera.getPicture(options).then((imageData) => {
  *  // imageData is either a base64 encoded string or a file URI
  *  // If it's base64:
- *  let base64Image = "data:image/jpeg;base64," + imageData;
+ *  let base64Image = 'data:image/jpeg;base64,' + imageData;
  * }, (err) => {
+ *  // Handle error
  * });
  * ```
  */