[COOK-2856] - first pass at attribute driven config
[COOK-2344] - preserve log settings

Don't set default values at all for the log settings, use the
Chef::Config defaults. This is better for Chef 11. A user can change
the attributes if they so desire.
[COOK-2856] - add tests for config
[COOK-2858] - implement include dir in client.rb
[COOK-2856], [COOK-2858] - update documentation
[COOK-2856] - incorporates feedback from review

* Clarify deprecated / replaced attributes.
* Add a comment about local variables for method use, and make the
  variables > 1 character long
Merge branch 'jtimberman/COOK-2856'