Added support for URLs as provided in WWfeedback messages

I had inadvertently provided an older version of CAS.pm when submitting
the original version.  This brings CAS.pm up to date.  The only change
was/is to add support to keep params on the URL being sent to the CAS server
(so that URLs provided by WWfeedback messages work properly).
Fixed copyright date, and minor code cleanup
Merge pull request #74 from paulvojta/master

CAS.pm:  update to current version, and some minor code changes