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.
add `node['datadog']['agent_version']` attribute

if this attribute is left unset, the existing behavior of "install the
latest version the first time the recipe is run, then never change it
again" is maintained.
first cut of namespaced attributes
Moved all the attributes into their own namespace
Merge pull request #46 from skottler/namespaced-attributes

Moved all the attributes into their own namespace
Allow repository installation to be optional

Fixes issue #48.
Fix a couple typos
Merge pull request #50 from dwradcliffe/patch-1

Fix a couple typos in namespaced attributes

Thanks @dwradcliffe