warn against using the plugin in combination with --net=weave
warn against using the plugin in combination with --net=weave

and expand the basic proxy usage docs slightly.

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