Initial version of the UAC code

Add SecureSocial as a dependency for the webapp.
Add SQL script to modify database schema for holding user identities and
sign-up tokens.
Create UserRepository and SignUpTokenRepository to query the database for
log-in information.
Replace the securesocial templates

Replace the default views provided by securesocial with custom
implementations. The custom views should have the same look & feel as the
rest of the application.