Dynamic maps

New map rendering "engine".

Also allows downloading maps off Berlin.

![screen shot 2013-10-03 at 8 40 17 pm](https://f.cloud.github.com/assets/351915/1266606/a234595e-2c8d-11e3-9c77-fdf77de8038e.png)

This is a small feature, no need for tests :wink:

@christianblais