MB-9883: send memcached request batches with single calls
MB-9883: send memcached request batches with single calls

That should produce even better results than delay_send option.

Change-Id: Iba0891cf2d0fda96f77a733baffed99cab57f0a5
Reviewed-on: http://review.couchbase.org/32701
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

membase/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,mschoch/ns_server,daverigby/ns_server,mschoch/ns_server,membase/ns_server,nimishzynga/ns_server,ceejatec/ns_server,ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,mschoch/ns_server,daverigby/ns_server,daverigby/ns_server,membase/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,ceejatec/ns_server,daverigby/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,ceejatec/ns_server,daverigby/ns_server,nimishzynga/ns_server,mschoch/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,membase/ns_server