Add support for gzip and deflate encoding on HTTP server response

Title says it.  Here are some numbers to back up my cause!  The bandwidth and time savings will be handy!  I am not sure if jQuery can do gzip'd requests, but certainly other API clients will be able to take advantage of this in the future.

```
Test conditions:
	4567 songs
	Google Chrome, Accept-Encoding: gzip,deflate
	Crappy internet connection

branch master:

/api/songs, prettyJson: true
	Size: 2.5MB
	Content: 2.5MB
	Time: 11.61s
	Latency: 529ms

/api/songs, prettyJson: false
	Size: 1.7MB
	Content: 1.7MB
	Time: 7.24s
	Latency: 629ms

branch http_gzip:
	
/api/songs, prettyJson: true
	Size: 204KB
	Content: 2.5MB
	Time: 1.82s
	Latency: 850ms

/api/songs, prettyJson: false
	Size: 188KB
	Content: 1.7MB
	Time: 962ms
	Latency: 620ms
```