Initial doc page

[terrytangyuan]

Just some initial code. Not sure what the doc structure you prefer though.

[terrytangyuan]

@perimosocordiae Travis failed due to this ill-conditioned problem again. Have you added a fixed seed for the test?

[terrytangyuan]

Run the following and then go to doc/build/html to see the html page built by Sphinx:

pip install Sphinx
cd metric-learn/doc
make html

[perimosocordiae]

Re: the flaky test, it's something that I'm aware of but haven't bothered to fix yet. I'll probably add a check in the code to prevent it at the source, if possible.
In the mean time, for non-code changes you can put the string [ci skip] in your commit message and it won't trigger a Travis run.

One consideration for docs: what kinds docs do we want to support building? I would probably only use the html docs, but if you have a case for other formats, that's fine.

Once we get the docs looking nice, I'll host the html docs on a gh-pages branch for easy access.

[terrytangyuan]

I see. Will do. Yep gh-pages is exactly what I have in mind!

[terrytangyuan]

@perimosocordiae Want to merge this first and host it? We can finish the docs later and I might need your help on this too since you are more familiar with the algorithms implemented.

[perimosocordiae]

Merged. Thanks for getting started on this!