First stab at recipe-based configuration.

Cassandra is in.
Include the recipe to only have to say recipe[datadog::cassandra]
Updated the version number
Update README.md
Taking another, simpler approach.

Using a resource & provider to configure a source to monitor.
Work in progress
Merge branch 'master' into integration-recipes
Merge branch 'integration-recipes' of github.com:DataDog/chef-datadog into integration-recipes
Added mysql, replace ambiguous monitor name with ddmonitor
Postgres passes.

Now it's a matter of applying the same logic to the rest of
the integrations.
More integrations converted to the new style
Merge branch 'master' into integration-recipes
Moving to arguments that can be passed to the monitor.
Enough scaffolding to test new-style integrations
Add new agent configuration templates
Add activemq, apache, cassandra to the list.
Add couchdb, elasticsearch, haproxy.
Updated readme
List does not exist, Array does.
Tested cassandra and couchdb.

These 2 should be used as templates for the rest of the integrations.