Windows fixes

[konstantint]

Changes useful for those installing the package on Windows

[jaredly]

Thanks for the help! It looks like you got rid of the mkdir -p -- don't we still need that? (or something like it)

[konstantint]

install.js does mkdirp anyway, doesn't it?

[Eoksni]

I just want to confirm that by following instructions in this pull request I managed to install this kernel on Win 10 with no problems.

[Eoksni]

Although I would make a recommendation to make it work with anaconda as well. Because when I ran install process from within anaconda console, it couldn't find Python, even though it is obviously there. So I had to install windows-build-tools to make python globally available (outside of anaconda), then this kernel installed itself.