Spruce up the landing screen.

"Launch Test Map" is under the menu options.

Apparently, the default Holo Light button is transparent, meaning I would have to re-create the styles just to get it to be opaque.  It's not worth the time.  For now, I snuck a white view underneath the button.

![device-2014-04-22-132326](https://cloud.githubusercontent.com/assets/2092627/2768302/540d91d8-ca43-11e3-9028-e688657b4684.png)


Credit to Benjin for the icon design.

![device-2014-04-22-132229](https://cloud.githubusercontent.com/assets/2092627/2768326/93371cf8-ca43-11e3-8fa2-8891cd76f42a.png)