Ready: Riak CS Multibag docs

- [x] Command line docs in **Riak CS Command Line Tools**
- [x] Configuration in `app.config`
- [x] Architectural description
- [x] Stanchion configuration
- [x] Etc.
Just a minor matter of degree, I prefer a little more equal treatment of CS and Stanchion.
For example: 
"Because  some of the special functionality required for Riak CS multibag
is contained in Stanchion along with Riak CS itself"