workbook prototype complete

[shrek]

A complete prototype of "workbook" functionality is available at:

http://github.com/shrek/socialcalc

The following "workbook" functionality is available:

1) add sheet
2) delete sheet
3) rename sheet
4) copy sheet
5) paste sheet

6) new workbook
7) save workbook
8) load workbook

I would appreciate help from User InterfaceI/User experience gurus to
help style the new "workbook" controls to flow well with the rest of
the UI.