Implements disableAcceptEncoding option to disable gzip encoding of response.

Livereload is not gzip-aware, so gzipped websites are not properly parsed on the "write" function.

Implementing gzip is both  
- costly (performance wise), given that it would need to uncompress and compress every gzipped response, and 
- difficult, given that "write" is synchronous and node zlib methods are all async.

Therefore, a simpler solution for development purposes is to simply remove the "Accept-Encoding" header sent by the browser.