This addition allows optional troubleshooting of issues by looking at
phpCAS's detailed debug log.

…ing-tickets.

Storing proxy-granting-tickets (PGTs) in a shared database facilitates serving Kurogo
from a cluster of web-hosts. Since the end-user and the CAS server may each make
requests to different hosts in the cluster the PGTs provided by the CAS server
must be placed in a shared location available to all other hosts.

This facility is provided by the underlying phpCAS library. This patch simply
allows its configuration via the Kurogo ini files.

…PGTStorageFile()

phpCAS 1.3+ no longer takes a 'format' argument for phpCAS::setPGTStorageFile().
This change allows proxy-ticket storage to work with all versions of phpCAS.

Conflicts:
	lib/Authentication/CASAuthentication.php

I'm including merging in this fix to the CASAuth_DB_PGT_storage feature branch
since it is a relatively minor fix and automatic merging with this feature
won't work due to the proximity of the changes.