Convert README to Asciidoc, enable TOC

[oleg-nenashev]

Currently the README is written in Markdown, and GitHub does not support automatic table of contents for it. We should rather convert the docs to Asciidoc and add proper macros

[MeatyFresh]

I'd like to tackle this. Not used Asciidoc before, good opportunity to learn about it.

[rdmueller]

@MeatyFresh If you use intellij and you have the asciidoc plugin installed, there will be a "convert to asciidoc" on the context / right click menu.

give it a try!

[MeatyFresh]

@rdmueller I was going to build the file manually, but I'll give IntelliJ a whirl. Thanks!