OPSINFRA-1524 - Update to Splunk 6.0.6

Also the command I was using for license segfaults so have to change that slightly.
Restore source line on Vagrant Berksfile

Apparently without the Source line, berks won't upload listed cookbooks.
Update Berkshelf API urls.

Code Review: http://crucible01.cerner.com/cru/OPSINFRA-CR-529#c742005
Update version of ChefDK

Also disable omnibus for the chef (server) vm that is having ChefDK installed on it anyways.
Updated Vagrant Boxes

Code Review: http://crucible01.cerner.com/cru/OPSINFRA-CR-515#c742156
Minor Documentation Tweaks

Code Review:
* http://crucible01.cerner.com/cru/OPSINFRA-CR-515#c732752
* http://crucible01.cerner.com/cru/OPSINFRA-CR-515#c732753
One more document generalization

Code Review: http://crucible01.cerner.com/cru/OPSINFRA-CR-515#c732754
Splunk 6.0.6 and Minor Cleanup

Internal Issues:
* OPSINFRA-1524
* OPSINFRA-1485