#17 Modified drag and zoom on the map display

[Martin Sjöblom]

File attached includes changes applied to two different versions of the code - 0.3.900 and 0.4.0_pre3327.

* Zoom relative to mouse pointer instead of center of the screen.
Keys, however, still zoom in on the center.

* Reverse x and y when dragging.
This gives a more accurate feeling of dragging the map.

Enjoy

[Martin Sjöblom]

Zipped source files