CASC-195

null check in ProxyGrantingTicketStorageImpl.
CASC-192

cast to XSAny in order to actually get the text content.
CASC-191

isValid method with simple implementation
CASC-168

added ability to specify class name in order to use a sub-class.
Merge pull request #33 from battags/master

NOJIRA fix minor missing final tags and javadoc.
Merge pull request #27 from battags/CASC-195

CASC-195
Merge pull request #29 from battags/CASC-191

CASC-191
Merge pull request #30 from battags/CASC-168

CASC-168
Merge pull request #28 from battags/CASC-192

CASC-192