Fix activeControlValid() for non-bound controls.

I have a set of controls that aren't bound to a bizobj directly - I
hook into the ValueChanged event. However, the ValueChange was being
delayed inside flushValue(), resulting in the modal dialog being
already closed by the time the event was fired.
Fixed multi-column printing with spanning objects.

An extraneous column change plus reprinting of the column headers
including spanning objects connecting incorrectly with the prior
column was happening in some cases even though we were at the end
of the report and there was nothing more to print.

Fixed by making sure we actually have stuff to print before
deciding to change columns.

Also, when changing columns, don't check ReprintHeaderOnNewPage,
but rather ReprintHeaderOnNewColumn.