Fix test/README
Fix test/README

Explicitly tell the user he should have a running Crossbar instance when attempting to run the tests (with at least a default configuration).
goeddea/autobahn-js,crossbario/autobahn-js,tavendo/AutobahnJS,Dynalon/autobahn-js,cantidio/autobahn-js,tavendo/AutobahnJS,Dynalon/autobahn-ts,goeddea/autobahn-js,cantidio/autobahn-js,oberstet/autobahn-js,Dynalon/autobahn-js,oberstet/autobahn-js,Dynalon/autobahn-ts,Dynalon/autobahn-js,Dynalon/autobahn-ts,tavendo/AutobahnJS,goeddea/autobahn-js,Dynalon/autobahn-js,crossbario/autobahn-js,oberstet/autobahn-js,cantidio/autobahn-js,Dynalon/autobahn-ts,crossbario/autobahn-js,crossbario/autobahn-js,oberstet/autobahn-js