Add timeout for long pooling connections and reconnect if connection breaks

I have added polling reconnect on periodical timeout and errors.

When ruining long session I come into situations where connection would brake. In those situations browser would still be able to send messages via skewer.log to skewer-repl buffer, bund commands wouldn't make it the other way. I am not entirely if it fixes all issues with dropping connection, but it seamed to help in my cases. What do you thing about this changes ?