Upgrade Jetty to 9.1.4
Add toString method to HTTP client Response
Fix hard coded max response size in JettyHttpClient
Work around bad buffer resizing code in Jetty client

The BufferingResponseListener built into Jetty client resizes the input
buffer on every call to onContent, which cause very poor performance.
This diff switched to a normal doubling strategy and eliminates the
final copy by returning a ByteArrayInputStream instead of a perfectly
sized byte array.
Remove gzip handler in jetty client