GitLab

This will allow hosting as Github Pages.

* Copied Tutorial from Google Code wiki.

* Initial Home page

* Copied How To Parse A Document from Google Code wiki

* Updated How To Parse A Document (markdown)

* Updated How To Parse A Document (markdown)

* Updated How To Parse A Document (Old API) (markdown)

* Copied How To Emit YAML from Google Code wiki

* Copied Breaking Changes from Google Code wiki

* Copied Strings from Google Code wiki

* Updated Strings (markdown)

* Updated Home (markdown)

* Fix typo.

* Updated Breaking Changes (markdown)

* Updated How To Parse A Document (Old API) (markdown)

* Updated Breaking Changes (markdown)

* Move wiki content to docs/

* Improve markdown and add colored code syntax
Co-authored-by: Jesse Beder <jbeder+github@gmail.com>