Two new mouse cursors (paintbrush and text I-bar) made by basse (he even made the patch!), inspired by Bart's page.
I also changed screenmain() ever so slightly, so that the standard cursor is always used when the mouse is over a window header.
This commit: selection code, loop cursor and menu option for 3d header committed.
Still to come will be activation code (perhaps shift-B rotation) after more discussion.
