Using branches and tags

[larseggert]

I'd suggest that the "main" branch (which we should rename "master" to, btw) be the main working branch going forward.

We should create a second branch ("published" or something like that) that we push the current tip of "main" to when that gets published on the website.

We should also create a revision and/or date tag when a new version is published.

This would allow us to get rid of Tao_Current.txt.

We should also get rid of Tao.html - what is that for anyway?