message parsing is too strict

[slingamn]

modern says that "These message parts, and parameters themselves, are separated by one or more ASCII SPACE characters (' ', 0x20)."

The current ircmsg.Parse implementation treats two consecutive spaces between parameters as an attempt to send an empty parameter as a non-trailing, and errors out; the user gets disconnected with Received malformed line. This is probably wrong.

[slingamn]

RFC1459 is explicit that this is allowed.

h/t @streaps for the report.