Add popcorn limiter

[stevenleeg]

When using /popcorn, limit the number of reconnects made. This way, if someone forgets to /unpopcorn, it won't connect to omegle forever.

Maybe implement something that logs the last time a non pipe'd user interacts with the bot. That way, for example, each time someone other than rochako talks to omeglebot it will reset a timer which would keep popcorn reconnecting.