Adding compiler settings from official repo.

The official repo has settings for the vim compiler and it would be nice to include them.

This is the original comment from the Golang Mercurial repo:

```
a1fe2e3fadb0 by David Bürgin <676c7473> on Jun 30, 2013   Diff
misc/vim: Add compiler plugin for Go

This change adds a basic compiler plugin
for Go. The plugin
integrates "go build" with Vim's ":make"
command and the
quickfix list.

Fixes  issue 5751 .
```