Rotate tool(New Map Tool)

A new MapTool for rotating multiple selected features interactively using mouse.

Normal Usage:
Select features on map. press mouse and drag to rotate about the selected features' boundingbox center.

Advanced Usage:
A cross appears on the boundingbox center of selection by default. Press "Control" key and move mouse(no pressing) to move this cross to the desired anchor position. Now press and drag mouse to rotate about this new anchor.

![Screenshot from 2013-01-06 13:48:18](https://f.cloud.github.com/assets/1298627/45796/90798258-57da-11e2-81fe-39ada2b046b8.png)

No icon provided yet. I have requested for one from Robert Szczepanek.