Fix dynamic routing zoom level

* Update `MapController#quarterOn()` to maintain current zoom level.
* Remove `MapController#setPosition()` method (only used by tests).
* Reduce default number of locations used to calculate average speed to 3.
* Update default routing zoom values in integers.xml.
* Remove unused integer resources for turn radius.
* Remove `MapController.ROUTE_ZOOM_LEVEL` constant. Route zoom level should always come from `ZoomController`.
Merge pull request #294 from mapzen/chuck/fix-route-zoom-level

Fix dynamic routing zoom level