Update extension icon when proxying to others

Ran grunt test.

Icon updates correctly when you start proxying, stop proxying, start providing (giving) but not when you stop providing. Should work once rtcToNet (in RemoteInstance) knows to close when corresponding socksToRtc is closed. 
Can this be removed completely?  I think you can remove it from the UIAPI interface in uproxy.ts if that's giving you problems (UIAPI should only contain methods/properties that are both in the real ui and ui connector objects)