Description of problem:
scrollwheel-zoom of the map should be centered at pointer position instead of map center

Version-Release number of selected component (if applicable):
fc17

How reproducible:
always

Steps to Reproduce:
1. in a tz-chooser map, move mouse pointer to the corner of the map
2. zoom in using a scroll wheel
3.
  
Actual results:
totally different area is under the mouse pointer now

Expected results:
place under the pointer should remain the same (like in most of online maps etc.)

Additional info: