warn against using plugin and proxy simultaneously
warn against using plugin and proxy simultaneously

and give a complete example.

Partially addresses #1988.

dpw/weave,n054/weave,dpw/weave,n054/weave,weaveworks/weave,n054/weave,n054/weave,dpw/weave,n054/weave,weaveworks/weave,paulbellamy/weave,paulbellamy/weave,paulbellamy/weave,weaveworks/weave,dpw/weave,paulbellamy/weave,dpw/weave,weaveworks/weave