Dialog no longer wraps questsions in blocks.  This is partly due to the
fact that the BEGINBLOCK/ENDBLOCK commands appear to be totally ignored
in all implementations of the debconf front-end.  The second reason for
removing the blocks was to add the ability to have skipped questsions in
a dialog.  This significantly changed the flow of the dialog algorithm
and actually cleaned things up quite a bit.

This commit includes cleaned up tests for removing the blocks as well as
new tests for the question skipping capabilities