Changes to note editor

 * Extend #499 to use app icon instead of "close" menu item
 * Remove the special 4.x layout for note editor
 * Check for unsaved changes before closing note editor
 * Increase resolution of media icon as it wasn't scaling well
 * Make note type and deck more prominent by moving them to the top of the list as spinners

![device-2014-09-27-230438](https://cloud.githubusercontent.com/assets/2818274/4430931/4dfb83da-464f-11e4-9514-e42eea52af44.png)