Namespace restricted route matching
Namespace restricted route matching

Allow routes to additionally specify a namespace attribute. When
no route is specified the _nsRouter.defaultRoute is assumed.

R=jeff.pihach, gary.poster
CC=
https://codereview.appspot.com/7396050

jrwren/juju-gui,jrwren/juju-gui,bac/juju-gui,mitechie/juju-gui,CanonicalJS/juju-gui,bac/juju-gui,bac/juju-gui,mitechie/juju-gui,jrwren/juju-gui,bac/juju-gui,CanonicalJS/juju-gui,mitechie/juju-gui,CanonicalJS/juju-gui,jrwren/juju-gui,mitechie/juju-gui