A zero-configuration convention for CAS test credentials.

Credentials are pairs (username, password).  Valid credentials are those
in which username == password.

This intentionally coincides with Jasig CAS Server's test mode.
Use URLs for configuring all test servers.
Add CAS server startup to CI test script.

Also add URL generation tasks for CAS and ladle-controlled LDAP.
JRuby-compatible spawn options.

This doesn't really do the same thing as the previous form, and it
doesn't actually do anything in JRuby 1.7.x.

However, the [:out, :err] => "/dev/null" form causes a program abort in
JRuby 1.7.x.  This form doesn't.
Merge pull request #31 from yipdw/decouple-cas

Decouple CAS process management from integration tests