Update docs and change license.

* More relevant. They are pretty much the same as when the software was
  first released and several aspects are not longer valid. Also some things
  could be clearer.
* This was under MIT but I really prefer my stuff to be public domain. Switched
  license. There are a few patches from others but they are not [legally
  significant](https://www.gnu.org/prep/maintain/maintain.html#Legally-Significant)
  and will soon be mostly removed anyway since they mostly relate to the
  error page which I will be removing.
* Took the wiki content, made it less verbose and moved it into the readme
  file.