This patch updates ruby-neovim to version 0.4.0, which includes the following changes:
- Add 'Neovim.executable' for accessing nvim info
- Fix bug where '$curwin' and '$curbuf' got out of sync after 'Vim.command' invocations
- Use 'vader.vim' for running vimscript acceptance tests
Signed-off-by: Federico Damián Schonborn <federicodamiansch@gmail.com>