Set HTTP response body to Buffer by default.

 On branch master
	modified:   docs/current/reference/http.md
	modified:   lib/http.js
	modified:   test/http_test.js
Adds a facade() method to HTTP response.

 On branch master
	modified:   lib/http.js
Adds Response docs to HTTP reference.

 On branch master
	modified:   docs/current/reference/http.md