Migrate wiki to main repo

[ringods]

On one hand, Github wikis are a great thing. But on the other hand, one of it's drawbacks is that only repo maintainers have update access to the wiki.

In open source, contributions should also work for documentation. As a result, my request would be that one of the maintainers migrate all the wiki content into the main repo, e.g. in a docs folder.

Once the documentation is there, contributions to this documentation would follow the usual Pull Request pattern.

[RobLoach]

I'd be down. We could even publish rendered docs over with githubpages at http://twigjs.github.io/twig.js/ .