wellington formula

Hi, I would like to add the [wellington](https://github.com/wellington/wellington) project to brew.  I'm new to building formulas, so any help would be great.  I noticed that go get ./... does not work well with brew.  I took tips from the other go projects to explicitly require all packages as go_resources, including the main repo which has 5 packages in it.

Questions:

* This formula is dependent on libsass which requires compiling c code, did I properly mark that requirement?
* I'd like to alias this project to `wt` which is the name of the cli tool, how is that done?
Since this isn't being statically linked, it doesn't need to get installed publicly - stage it into the buildpath instead, and add it to `PKG_CONFIG_PATH` so it can be found.

```ruby
system "./configure", "--prefix=#{buildpath}/libsass",

...

ENV.append_path "PKG_CONFIG_PATH", buildpath/"libsass/lib/pkgconfig"
```