guarding against missing options object in Router constructor when invoked from createClass()
guarding against missing options object in Router constructor when invoked from createClass()

assuring that super() can be called without arguments.

reviewed by @jhusain
trxcllnt/falcor-router,Netflix/falcor-router,michaelbpaulson/falcor-router,jontewks/falcor-router,mitel/falcor-router,drager/falcor-router,kristianmandrup/falcor-router,osxi/falcor-router,jmnarloch/falcor-router