#28 Add setRealm(Object) to SecurityRealmInterface

[David D. Kilzer]

Per the SecurityConfig.addRealm() method, realm
adapters that implement SecurityRealmInterface must
have a setRealm(Object) method.

The attached patch adds this method to
SecurityRealmInterface, and implements it for the
SimpleSecurityRealmBase class.

[David D. Kilzer]

Implement SecurityRealmInterface.setRealm(Object)