OSX appbundle and some

* Maven task to create OSX App
* Some OSX - specific code, like swapping `CTRL` shortcuts to `CMD` shortcut, and placing menubar on top of the screen.
* OSX icon support, all the way to Retina resolution.
* Sketch.app source file for icons - need some improvement, though..

still need some testing, as I only able to test on 10.9, with latest Java 1.7 from Oracle.
also pardon for any mistakes, this is my first `java`/`maven` adventure :)