_OPEN{CONNECTION, HOST, CLIENT}, _CONNECTIONADDRESS$ now do something, as the underlying tcp routines
are implemented (with the exception of tcp_connected and thus _CONNECTED).
Floats previously only rounded to the upper limit of a signed integer64;
this alteration will now round them to the unsigned integer64 limit if
possible, or else toss an "OVERFLOW ERROR" if there's no way to squeeze
the float's value into an integer64.