Blender Git Loki

Fix for bug #1145 bevel numbutton not changing when clicking on the sides

http://projects.blender.org/tracker/index.php?func=detail&aid=1145&group_id=9&atid=125

I changed the fbutton function to give the possibility to control the a1 and a2 parameters of the button.

This commit also fixes two things in the bevel function:
- The numbut didn't do anything because it wasn't recalculating the proper variable
- The display wasn't recalculated when pressing Ctrl or Shift (it's now done by recalculating after every keyboard event. I've done it this way since the event loops seems to skip CTRL and SHIFT events)