feat(crop): add crop plugin (#284)

src/plugins/crop.ts

@@ -0,0 +1,34 @@
+import {Cordova, Plugin} from './plugin';
+/**
+ * @name Crop
+ * @description Crops images
+ * @usage
+ * ```
+ * import {Crop} from 'ionic-native';
+ *
+ * ...
+ *
+ * Crop.crop('path/to/image.jpg', {quality: 75})
+ *   .then(
+ *     newImage => console.log("new image path is: " + newImage),
+ *     error => console.error("Error cropping image", error)
+ *   );
+ * ```
+ */
+@Plugin({
+  plugin: 'cordova-plugin-crop',
+  pluginRef: 'plugins',
+  repo: 'https://github.com/jeduan/cordova-plugin-crop'
+})
+export class Crop {
+  /**
+   * Crops an image
+   * @param pathToImage
+   * @param options
+   * @return {Promise<string>} Returns a promise that resolves with the new image path, or rejects if failed to crop.
+   */
+  @Cordova({
+    callbackOrder: 'reverse'
+  })
+  static crop(pathToImage: string, options?: {quality: number}): Promise<string> {return; }
+}