BROOKLYN-51

If no security properties are set and `--noConsoleSecurity` is not set then `BrooklynLauncher` configures the server to accept unsecured connections from `127.0.0.1` and secured external connections that are authenticated with the user `brooklyn` and a randomly generated password that is logged once. 

The new security filter checks the remote address of the request. I'm assuming that this can't be spoofed.
I think this is right, but just wanted to raise question... with `ExplicitUsersSecurityProvider.authenticate` it will look up the users+passwords from brooklyn properties, so a properties-reload will affect subsequent authenticate attempts (but not existing sessions). However, if we've set it to use `BrooklynUserWithRandomPasswordSecurityProvider` then the properties-reload to add explicit users + passwords will have no affect. I think that's fine as we've logged to tell the person starting brooklyn, so they can restart if desired.