Switch to MapQuest tileserver

The official OSM tile server should not be used in applications.
MapQuest is free and also allows to display a satellite map (which
unfortunately only goes to zoomLevel 10).

More info:
http://wiki.openstreetmap.org/wiki/Tile_usage_policy

Change-Id: Ia5e0d2c99ea4d8f3989f8460c778bf748c5b68b5
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Add credits for MapQuest and OSM data/services.

Change-Id: I66bb2ef931384d5894d445a81d66e109dc0b946a
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Remove offset from PlaceSearchModel documentation

The offset property was removed by
1d0966c6924876655c52725e779a7aa24866ff60.

Change-Id: Id46e1b6f97e70d38eaef8813be2543293f423fab
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>