Allow more configurability in production builds.

```
DISABLE_ES3=true DISABLE_JSHINT=true DISABLE_MIN=true ember serve --environment=production
```

Takes initial production build time from 70s to 21s, and rebuilds from 6s to 2s.

```bash
% DISABLE_ES3=true DISABLE_JSHINT=true DISABLE_MIN=true ember serve --environment=production
version: 0.0.46
Livereload server on port 35729
Serving on http://0.0.0.0:4200

Build successful - 21433ms.

Slowest Trees                  | Total
-------------------------------+----------------
DefeatureifyFilter             | 4363ms
DefeatureifyFilter             | 4308ms
TranspilerFilter               | 2773ms
TranspilerFilter               | 2001ms
DefeatureifyFilter             | 1860ms
DefeatureifyFilter             | 1644ms

file changed main.js

Build successful - 2355ms.

Slowest Trees                  | Total
-------------------------------+----------------
ReplaceFilter                  | 159ms
DefeatureifyFilter             | 119ms
```
@stefanpenner - Your wish is my command. ;)