Modified initial documentation part 1.

[Offlein]

Hey @dpimonov thanks for your patience. Here's a first pass at improving the initial experience of the documentation.

I see there's a number of very minor English language specific things that I'll try to tweak in a next pass. And of course you don't have to use this in its exact form (or at all) -- no hard feelings either way of course!

Thanks for this package.

[dpimonov]

Hi @Offlein, so far I like the changes. Keep going. Until there are no additinal folder for docs - I think it is better to keep navigation menu which was removed.