This is the next phase of the work to create business logic objects for Gift and GL batches.
Just a couple of fixes to places which gave us a problem with loading a screen.  The string checks did not allow for being called when the table is null (which it is by default!) and the filter panel was storing up validation errors when the screen was not fully loaded, which resulted in the focus going to unexpected places after the first control was validated.
Remove unused variables
Stupidly left these changes out of the last commit that dealt with unused variables
Fixed conflict from Christian's correction to my stupid checkin from my last branch
merge from lp:~alan-paterson/openpetraorg/2014_09_30_gl_and_gift