Increase usefulness of Agent diagnostic commands

This update adds the following:
 - Added color and error-resolving hints to 'monasca-forwarder info'
 - Made 'monasca-collector check <checkname>' output more human-readable
 - Added 'monasca-collector check_all' parameter to run all configured checks

Change-Id: I752eeddebc0bdd47a515d4af5affb6d850b44b0d