Subtree merge in Git-Tfs wiki repo

Resolves #383
Fix links to wiki.
mv config.md into the one doc dir
Move the old home wiki page so that it's the default file in the doc dir.
Updated links.

* All file names are lowercase.
* All command docs are in the `commands/` directory.
* A couple of useless files are gone.
contributing update.
Merge pull request #385 from sc68cal/docs and spraints/docs

Move docs from the wiki to the repo.