Need some docs darm it!

I took the documentation templates that I have gotten reasonably nice for dttxml and tacked them into pydarm. Feel free to use or not. I figure it would be a useful starting point. To build, go to the docs folder and do "make html" or "make livehtml". Livehtml will rebuild and refresh the page as you edit. wowie.

The documentation currently will be autogenerated in CI and look like this https://lee-mcculler.docs.ligo.org/pydarm/index.html

The CI settings could be made a bit more efficient to use the same image as the testing.

I also add a "conftest.py" so that you can use py.test (it is or will be documented a bit). It is remarkably more lightweight and easier to run than unit test and with fixtures, you can make tests that make plots more easily.