Update docs
Update docs

Add id's to examples.
Add description of merge_metrics flag.

Change-Id: I350f39ac531ff67ad80c8ae23a07ba1daa84b930

stackforge/monasca-api,hpcloud-mon/monasca-events-api,hpcloud-mon/monasca-events-api,hpcloud-mon/monasca-events-api,openstack/monasca-api,sapcc/monasca-api,stackforge/monasca-api,oneilcin/monasca-events-api,sapcc/monasca-api,sapcc/monasca-api,stackforge/monasca-api,oneilcin/monasca-events-api,oneilcin/monasca-events-api,openstack/monasca-api,openstack/monasca-api,stackforge/monasca-api,hpcloud-mon/monasca-events-api,oneilcin/monasca-events-api