Initial hieroglyph slides

This configuration does a few things:

* Default html build does not build anything under ``slides`` (based on the ``excludes_patterns`` config in ``conf.py``. Since I'm changing the buildroot of the slides make command, it also includes anything under that when you build slides too.
* Builds slides as a slides sub directory of the content

**NOTE: I had to make a separate doctree directory for each build otherwise sphinx would complain.**
do we have a standard for shortening this? It'd be nice to be able to know what everything it shortened to without looking. Previously we've just done it at whatever seems good afaik.