Revision 1591

Fixed problem in logic which kept an edited problem from reading the
.tmp file when the answer was submitted.  Now the editMode variable
and sourceFilePath variables are passed on as hidden variables by
Problem.pm if they exists in the input form.  This fixes bug #179
as well as bug #109.

The temporary file is now labeled   fileName.pg.user.tmp where user is
the login name of the person editing the file.  If that file exists
then pgProblemEditor will attempt to use that as a source file.
The revert button forces a read from fileName.pg

--Mike