Brew Config: Go support

Adds a dash of Go support to the Brew Config to accompany the recent wider language support @mistydemeo weaved in.

Relates to this [comment](https://github.com/Homebrew/homebrew/issues/32014#issuecomment
-54135658).

Produces the output:

```
Go: /usr/local/bin/go => /usr/local/Cellar/go/1.3.1/libexec/bin/go
GoPath: /Users/Bob/go
```
@mikemcquaid The whole thing or just the ``` GOPATH ``` element?

@mistydemeo - That's a good question, actually. I haven't yet installed anything via Homebrew that interacts with Go, other than Go itself, and consequently I have a pretty static ``` $GOPATH ```. I will find a Homebrew formula that utilises Go and install it and see if that causes any issues with that element - Is there anything particular that you recommend?