Merge pull request #49 from scottpurdy/datadog-module

Make datadog a module in grokcli for easy 'python -m grokcli.datadog' ex...
Merge pull request #50 from jcasner/master

MER-2296 fix autostack filter format for --preview option
Adds Datadog PDF and note in the README about Datadog integration.
Adds command for seeing Datadog CLI help.
Merge pull request #51 from scottpurdy/develop

Adds Datadog PDF and note in the README about Datadog integration.
Merge commit '930803398d03017357211f3cc079d29c07398b3b' into 1.1.1-hotfix