re-add support for multi-valued attributes

Add tests for ensure re-add support for multi-valued attributes is working
Merge pull request #1 from katelme/patch-1

CASC-196
Merge branch 'master' of github.com:battags/java-cas-client
Merge branch 'master' of github.com:Jasig/java-cas-client
CASC-207

Converted logger to static for de-serialization purposes.
Merge pull request #50 from battags/CASC-207

CASC-207 - Converted to static logger for serializable class