feat(shake): add Shake plugin (#426)

closes #313

src/plugins/shake.ts

@@ -0,0 +1,35 @@
+import {Plugin, Cordova} from './plugin';
+import {Observable} from 'rxjs/Observable';
+/**
+ * @name Shake
+ * @description Handles shake gesture
+ * @usage
+ * ```typescript
+ * import {Shake} from 'ionic-native';
+ *
+ * let watch = Shake.startWatch(60).subscribe(() => {
+ *   // do something
+ *   });
+ *
+ * watch.unsubscribe();
+ * ```
+ */
+@Plugin({
+  plugin: 'cordova-plugin-shake',
+  pluginRef: 'shake',
+  repo: 'https://github.com/leecrossley/cordova-plugin-shake'
+})
+export class Shake {
+  /**
+   * Watch for shake gesture
+   * @param sensitivity {number} Optional sensitivity parameter. Defaults to 40
+   */
+  @Cordova({
+    observable: true,
+    clearFunction: 'stopWatch',
+    successIndex: 0,
+    errorIndex: 2
+  })
+  static startWatch(sensitivity?: number): Observable<any> {return; }
+
+}