Add gesture to make any 2D map 3D

[mvl22]

The iPhone app v. 3.0 which is currently in Apple review (so out very soon) has a useful two-finger pinch mode, i.e. two fingers (about an inch apart, side-by-side - i.e. directly next to each other, not one above the other) dragged upwards, turns the map from 2D to 3D by angling it as the fingers are moved.

I miss this in the Windows Phone app!