Issue #300 - Implement Deflater Pool
Removed the ThreadLocal pooling of deflaters in GzipHandler in favour of a new DeflaterPool class
GzipHttpOutputInterceptor.GzipBufferCB now recycles the Deflater in onCompleteFailure()
added benchmark for the DeflaterPool
allow negative capacity to mean no limit on the pool size
added mod file and xml changes
replace setDeflaterPool with newDeflaterPool
Signed-off-by: Lachlan Roberts <lachlan@webtide.com>