This option makes it so that your thesis has two co-chairs.

The changes were kindly contributed by Dav Clark.
Fix the abstract page for co-chairs

\abstract definition lacked co-chair support. Also, in my personal copy, I've commented out the abstractsignature(b) macros. I don't think it does anything anymore.
Merge remote-tracking branch 'source/option-co-chairs'

Conflicts:
	myucthesis.cls