Genie:  Don't throw kOTFlowErr on socket writes

Don't throw an exception when the underlying Open Transport endpoint has
a buffer overrun.  If we have any data, return it, or if we're blocking,
keep trying.
Genie:  Check FIN flag after count to avoid race

Check it_has_received_FIN after calling OTCountDataBytes() (though still
before checking its result) to avoid the race condition without the need
for an OTNotify critical section.
Genie:  Check RST flag after send to avoid race

Check it_has_received_RST after calling OTSnd() (but before checking its
result) to avoid the race condition without needing an OTNotify critical
section.
Genie:  Clean up OTSocket
Merge branch 'no-OTNotify-critical-sections'

Avoid calling OTEnterNotifier() and OTLeaveNotifier(), which don't exist
in Open Transport 1.1.0.

(The "tilisten" module also doesn't exist in 1.1.0, but this will result
only in an error from listen(), not a crash, and a TCP server won't ever
be a prerequisite for acquiring a newer Open Transport update, whereas a
TCP client might be.)