Localtunnel integration

[naholyr]

Proposal to fix #15

• Client: Dumb test to allow localtunnel to work by disabling "websocket" transport if URL matches "*.localtunnel.me". Ideas welcome to make it more robust.
• Server: Add an option "-l" to open localtunnel on startup.
  • [x] Done: customize subdomain (by adding a parameter "-l subdomain")
  • [x] Done: request previous subdomain on next startup
  • [x] Maybe: generate an easier random subdomain like "copycast{few digits}"
  • I think we won't be able to find a smart enough generator, it's easier to let user decide, as he can type it once and it will be remembered for next times it's not too much of a PITA
  • [x] Maybe: handle network errors, automatic restarts, etc…
  • During my tests it looks like the programmatic client already handles reconnections, should be tested
  • [x] Maybe: open a tunnel while already started by pressing a keyboard key
  • Introduce too much complexity for too few gain, not sure it'd be a smart move

Discuss the "Maybe"s

[naholyr]

Ping @Delapouite for review

[Delapouite]

LGTM