Change SocksToRtc to have a freedom-compatible interface.

This change also adds a manifest.json for SocksToRtc, but this
manifest is not yet used anywhere or verified by the build.
Change from "onceStopped()" to "on('stopped', ...)".
Unbreak tests
Merge pull request #170 from uProxy/bemasc-rtc-modules

Change SocksToRtc to have a freedom-compatible interface.