[cells] improved IOCenter debuggability
[cells] improved IOCenter debuggability

This adds cells names and makes ErrorQueue instance 'public'

Change-Id: I61818e64cd0d5782223d8fc44b88cda1fe04ab74
Reviewed-on: http://review.couchbase.org/9981
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Benjamin Young <fe09bc2ef2737a3258f978e26226dcbac1b3f948@couchbase.com>

ceejatec/ns_server,daverigby/ns_server,membase/ns_server,vzasade/ns_server,daverigby/ns_server,ceejatec/ns_server,nimishzynga/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,membase/ns_server,mschoch/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,membase/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server,nimishzynga/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,membase/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,mschoch/ns_server,daverigby/ns_server,membase/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server,vzasade/ns_server,nimishzynga/ns_server