Broke price information out into estimated and actual price columns. Not entirely...

Broke price information out into estimated and actual price columns.  Not entirely sure we want
these to be broken out, but it's trivial to pull them back into a single column if not.

I have an editor in place for setting the prices, but I'm trying to understand how one
captures the edited data when you are editing a column that is not part of the grid's
data model.  Bueller?

git-svn-id: svn://svn.open-ils.org/ILS/branches/acq-experiment@10101 dcc99617-32d9-48b4-a31d-7c20da2025e4