rotate map around a shifted center

[Martin Kolman]

per ​http://talk.maemo.org/showpost.php?p=761988&postcount=18|request:

• when the turn-by-turn navigation is active, move the position indicator down and show more of the map in the direction of travel

possible drawbacks:

• text orientation on tiled maps (aerial/sat tiles dont have text usually, so they should be OK)
• performance -> maybe use some sort of acceleration (OpenGL ES?)
  • seems to be OK, should be a non issue in the clutter based alternative map widget (once implemented :)

[Martin Kolman]

ADDED map rotation in the direction of travel, the position indicator shifting is next

[Martin Kolman]

• implemented in V0.22-3
• NOTE: both centering and map rotation must be on for this work :)