CASC-174 Provide facility for Servlet 3.0 programmatic JAAS login.

Servlet3AuthenticationFilter supersede the JBoss-specific
WebAuthenticationFilter for JBoss 7. It should also provide support for
programmatic JAAS login for any container that is Servlet 3.0/JEE6
compliant.
CASC-174 Remove JBoss verbiage from error message.
CASC-174 Remove @version javadoc tag.
Merge pull request #56 from serac/CASC-174

CASC-174 Provide Programmatic JAAS Login Facility for JBoss 7