removing scrubber
Merge branch 'master' of http://github.com/openwebwork/pg into bugfixes

Conflicts:
	macros/PGessaymacros.pl
Merge pull request #52 from goehle/bugfixes

I'm going to break protocol and merge this.  The reason is that scrubber has already been removed from webwork2/master, which means that it is no longer available in PG.  Consequently essay answers are broken until this gets merged.