add mp4 mime/type

Use HTTPS Github URLs, instead of Git

ability to use env vars in proxies origin with `${}`

```
$ heroku buildpacks:set git://github.com/hone/heroku-buildpack-static.git
 ▸    Invalid buildpack `git://github.com/hone/heroku-buildpack-static.git`
```

MIME type "text/html" is already included by default

See http://nginx.org/en/docs/http/ngx_http_gzip_module.html#gzip_types

* container stopped
* file handles closed

This reverts commit 64dc2b1b.

this is a good blend of on the fly cpu utilization with file size
Thanks @jmervine

Ordered Routing

The requests will try to match based on this order top-down irregardless of which options are used:

* Root Files
* Clean URLs
* Proxies
* Redirects
* Custom Routes
* 404

CircleCI

* move spec docker things into spec/support/docker/
* rake shell now copies src files into /app/ and generates nginx.conf
* rake server[fixture] will now boot an nginx server locally