Load/Save feature for the database designer

Hi,

Luis sent me his last patch to support load/save features for the
database designer. It's a quite simple patch, and works flawlessly
AFAICT.

I'd like to commit it this afternoon, so if you want to look at it
first, you need to move fast :)

Patch attached with a few fixes from me.


--
Guillaume
  http://blog.guillaume.lelarge.info
  http://www.dalibo.com