Removed "Code" column from CommTrack program list

I removed the "Code" column from the programs.html template.

See [case 145210](http://manage.dimagi.com/default.asp?145210) for details of the case.

Knockout will not be affected by the removed column.

If the "code" attribute of program instances is never used -- I haven't checked -- we may want to remove the attribute from the model/document. I'm leaving it for now.