A new method, Reconnect, is added to tor controller which can be used to
reset the current connection. This will be later used in healthcheck to
help us reset the connection to Tor Daemon.
This commit adds a new response reader which replaces the old
textproto.Reader.ReadResponse. The older reader cannot handle the case
when the reply from Tor server contains a data reply line, which uses
the symbol "+" to signal such a case.
