Feature/issue 567 manual 2.3.0

#### Summary:

(1) Removes CmdStan doc from Stan manual, and (2) update with all comments on issue #567 

#### Intended Effect:

The summary says it all in terms of effect on this repo. 

The CmdStan doc is moving to the `stan-dev/cmdstan` repo with corresponding web-site updates for distribution.

#### How to Verify:

Make the doc and inspect.  The doc is still making as version 2.2.0 file name until the Stan version numbers change in the C++.  

#### Side Effects:

No. 

#### Documentation:

It's all doc.

#### Reviewer Suggestions:

Anyone.