Make gist documentation more accessible

[rjyounes]

1. Add link to gist-docs repo on the gist repo readme
2. Add link to widoco page to gist repo and gist-docs readme
3. gist-docs repo needs an index.html page with links

[Jamie-SA]

I deleted my previous comment because I had misread the original request.

1. I will be submitting a PR for this
2. The Widoco page is program generated. Unless someone says otherwise I'm going to guess that this is not a normal part of the Widoco output.
3. This will need to be done in the gist-docs repo, not here. I will create an issue for it over there.