Install and use neovim by default

[cjcjameson]

This cushions against the following error, caused by the vim-go
plugin, which is installed by the vim-config (separate repo):

> vim-go requires Vim 7.4.1689 or Neovim, but you're using an older version.
> Please update your Vim for the best vim-go experience.
> If you really want to continue you can set this to make the error go away:
>     let g:go_version_warning = 0
> Note that some features may error out or behave incorrectly.
> Please do not report bugs unless you're using Vim 7.4.1689 or newer.

Also, neovim is faster.

Necessary for this, I re-ordered some of the major modules in the main
setup.sh script so that if we fail halfway through, we don't have
configuration which refers to a binary (nvim) that isn't installed yet

Reopens and resolves #93

Note the alias -- is that how we want to be installing things like this? I'm used to it, but are there cases where it doesn't work well? At initial glance, neovim is doing well to pick up our existing configuration.

[nertzy]

I like this idea. I’ll give it a try soon.

[d]

Why is this necessary? I just checked two workstations, and vim --version reported VIM - Vi IMproved 8.0 (2016 Sep 12, compiled Jul 26 2017 19:10:24). which vim reported /usr/bin/vim

[nertzy]

Well, there are a couple different approaches. Right now we are installing macvim via a Homebrew cask. It looks to me like we fall back to the system vim on the terminal. I bet the version is different based on which OS version you’re on. We could install a newer standard vim via Homebrew, or we could install neovim. I admit I don’t actually know what neovim does differently, but I’ve heard that it’s popular at Pivotal recently.

[cjcjameson]

With the system vim I wasn't able to use "+y to yank to the system paste-buffer, but after installing neovim I am. This is not a vim/neovim thing, but it seems that the brew formula for compiling neovim enables something the system vim doesn't have.

Looking at https://stackoverflow.com/a/11489440 and specifically the following passage:

Be aware that copying/pasting from the system clipboard will not work if :echo has('clipboard') returns 0. In this case, vim is not compiled with the +clipboard feature and you'll have to install a different version or recompile it. Some linux distros supply a minimal vim installation by default, but generally if you install the vim-gtk package you can get the extra features.

With system vim, :echo has('clipboard') indeed returns 0, whereas with the neovim from brew, it returns 1.

[dotyjim-work]

On a workstation imaged today with macOS Sierra /usr/bin/vim --version reports 7.4. A brew installed vim installs at /usr/local/bin/vim --version reports 8.0 (and +clipboard). If there are objections to nvim a brew install vim an alternative to this PR.

[nertzy]

I like this and want to merge it. Unfortunately I realize now that the vim config we include pivotal/vim-config does not set up anything for neovim, so I believe some users would be confused as to why nvim has none of the usual customizations. I want to remedy that first before moving forward. (I maintain that repo, although don't really vim much anymore) There's an issue at pivotal-legacy/vim-config#4.

Another option would be to switch to @luan's vim-config which I believe does support neovim.

[luan]

@nertzy you seem to have grabbed the wrong link there. My config (vim/neovim) lives here. Although I have started to create a new, better documented, with discover-able bindings that only supports neovim (no regular vim) here if anyone is interested in trying that out.

[joemoore]

We are declaring PR bankruptcy as per #295.

Please review recent changes and direction and resubmit if needed. For example, we are are only installing Vim and VSCode by default, leaving others optional.

Thank you!