Support feature_negotiation just a little bit
Revert "Do not re-up RDY now that NSQ doesn't decrement RDY count server-side"

This reverts commit f615c76243474004caf50ca6b38e50d14a5de93a.
Added spec for when max_in_flight is greater than what the server supports
Only send RDY re-ups if the server needs them (i.e. < 0.3.0)