Update doc for Jekyll
Update documentation

Add a README file, and exclude some files from Jekyll
Describe installation
Fix typo in doc of FFI part
Fix typo in doc
Describe simplified install

The rockspec has now been added to the main torch rocks list.
Fix squashed list in doc
Use redcarpet to generate ToC, and style it

That was epic time struggling with Jekyll and redcarpet and CSS,
but at least it starts to look like something reasonable.
Remove old CSS
Remove unused file
Tweak headers

Hard to decide whether to have one single H1 tag for the title
then H2 tags below, or to have a H1 tag for each section.
Settling on this for now.

In the future, ideally would like to flexibly set the depth
of the TOC, thus simplifying the stylesheet. That will be
in Redcarpet 3.0 with option nesting_level, which will be supported
in Jekyll 2.0 but not before.

Or I could always write a plugin that truncates the toc at a certain
depth. But I'd rather code the Dirichlet distribution :)
Fix-up the presentation of the auto-extracted doc
Fix title of doc
Provide example

This is important, we precise how the functions are vectorized.
Fix link to tests
Precisions about the python documentation
Document multivariateGaussianRand

Closes #13
Update documentation with list of Randomkit rng
Change title of doc page and simplify _config
Document it