Add 2-Way binded view and center for map

[atd-schubert]

The map-component should also have summarized 2 way binded values view and center.

Center is a combination of lat and lng, view is like center with the zoom-level in addition...

[4thel00z]

@atd-schubert could I have more details on this?

[atd-schubert]

Currently we use lat and lng as directive input and output with datatype numbers, but we thought about to provide also center as input/output with datatype LatLng and maybe also view as tuple of [LatLng, number], where LatLng is the center position and the number is the zoom level. But maybe it produces a lot more complexity without giving any really new feature.