#129 fix

MobileElement is touchable now. Here are available methods:

```java
/**
	 * Convenience method for tapping the center of the given element
	 * 
	 * @param fingers
	 *            number of fingers/appendages to tap with
	 * @param duration
	 *            how long between pressing down, and lifting fingers/appendages
	 */
element.tap(int fingers, int duration);

/**
    * Convenience method for pinching the given element.
	* "pinching" refers to the action of two appendages pressing the screen and sliding towards each other.
	* NOTE:
	* This convenience method places the initial touches around the element, if this would happen to place one of them
	* off the screen, appium with return an outOfBounds error. In this case, revert to using the MultiTouchAction api
    * instead of this method.
	*
*/
element.pinch();

/**
	   * Convenience method for "zooming in" on the given element.
	   * "zooming in" refers to the action of two appendages pressing the screen and sliding away from each other.
	   * NOTE:
	   * This convenience method slides touches away from the element, if this would happen to place one of them
	   * off the screen, appium will return an outOfBounds error. In this case, revert to using the MultiTouchAction api
	   * instead of this method.
	   */
element.zoom();

/**
		 * Convenience method for swiping across the given element
		 *
		 * @param duration
		 *            amount of time in milliseconds for the entire swipe action to
		 *            take
		 */
element.swipe(int duration);
```