Crowd's context path should be included in `crowd.base` option

This project looks promising! But one thing I saw right away:

The `/crowd` part of the rest urls should not be hard coded. I assume it is quite common to access Crowd on the server root, for example `https://crowd.example.com/rest/usermanagement/...`.

Thus the hard coded rest paths should start with "/rest/..." and documentation fixed accordingly, as the default base path should anyway include the "/crowd" suffix.