Minor improvements and new map types.

Improved a little the way getter works.
BIG THING: added new map types. Now we have:

1. 'map': the normal map type. This is the default.
2. 'smart': a map with most of the colors grayed out. Useful for data visualization.
3. 'pt': a smart map where the tiles also contain the public transport lines.
4. 'satellite': satellite view.
5. 'terrain': terrain view.
6. 'community': HERE Maps community layer.
7. 'satcommunity': HERE Maps community layer with satellite imagery.
8. 'traffic': traffic layer.