For very high-speed message systems, the memory used for recovery can get to
be very large. The corrent limitation on that reduction is the ZMQ_RECOVERY_IVL
of 1 sec. I added in an additional option ZMQ_RECOVERY_IVL_MSEC, which is the
Recovery Interval in milliseconds. If used, this will override the previous
one, and allow you to set a sub-second recovery interval. If not set, the
default behavior is to use ZMQ_RECOVERY_IVL.
Signed-off-by: Bob Beaty <rbeaty@peak6.com>