Removed reel/explorer

Reel/Explorer was causing DCell to attempt connection and or spawn threads anytime dcell was required. This may seem like a fairly destructive pull request, but I really feel strongly that such functionality shouldn't be getting auto included into the main library, so I didn't bother trying to track down any further the specific problem. Pulled it out and all is well now. Explorer could easily be moved into a dcell_explorer gem/repo IMO.