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
Merge pull request #49 from kiall/issue-48

Allow repository installation to be optional
Merge pull request #45 from dcrosta/agent-version

add `node['datadog']['agent_version']` attribute
loosen chef-handler dependency fixes #51
Merge pull request #52 from grosser/handler

Update chef-handler dependency fixes #51
Same travis config as chefspec
Merge branch 'namespaced-attributes'
Match 3.6.x logging configuration
Fix Fauxhai syntax
Merge pull request #54 from isbaran/master

Fix Fauxhai syntax error
updated gemfiles for inclusion of root Gemfile, since it's not a gemspec
forgot to clean up the Gemfile
moves berks action to be part of the default task
execute test tasks within bundle context