[keycloak-dev] added a keycloak-common module

[Bill Burke]

The SAML adapter had some dependencies on classes within keycloak-core. 
  Unfortunately though, keycloak-core brings in Jackson JSON parser. 
So, I split out keycloak-core into keycloak-common and keycloak-core.

PR is pending, but it should be in when the Europeans wake up.

-- 
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com