Support Vim under Windows

[Carlo Delle Donne]

Support for Neovim under Windows has been added in #40. However, the plugin does not work in Vim under Windows yet.

[Carlo Delle Donne]

Running the following in Vim on Windows

let term = term_start('NONE') | wincmd p
let termtty = term_gettty(term, 1)
call writefile(['Test'], termtty, 'b')

results in

E482: Can't create file \\.\pipe\vim-10940-in-2