Sverchok API documentation

Created by: portnov

At current state, we have in sverchok.utils a big collection of useful function and classes, that can be used to write scripted nodes, or addons extending Sverchok. Some of these functions are even documented in docstrings. But at the moment the user / developer who wants to write a (scripted) node doesn't even see which modules we have, until he opens source code.

So, the proposal is to generate API documentation using one of existing tools, and publish it at github.io, similar to what we have for user documentation. At the moment, docstrings are rare and not so good, but if we know that they are published we will probably enhance them over the time. And even simple list of modules, classes and methods is useful, imho.

I'm not sure, for what exactly parts of Sverchok should we generate documentation. Probably just for sverchok.utils.

Also, we can discuss if it is good to generate documentation for all top-level classes and methods, or maybe we want to hide something (that will require some fuss with documentation generation tools, but certainly doable).

I managed to generate such documentation for sverchok.utils and sverchok.ui subpackages. Please check it out: sverchok.zip

@zeffii @Durman ?