Upgrade to XNIO 3.2
UNDERTOW-118 TCCL not set on HttpUpgradeHandler invocation
- improves performance of HttpString#appendTo(ByteBuffer)
  by using the bulk put method of ByteBuffer.
  Subclasses of ByteBuffer provide optimized implementations of
  the bulk put method which does not use a loop over the byte array.
Change websockets to add the filter on demand
UNDERTOW-112 Fix chunking performance issues by using writeFinal to write the chunk terminator
Fix NPE
Add option to ignore explicit flush for performance reasons
UNDERTOW-117 Implement cache expiration for files based on the Xnio watch service
UNDERTOW-119 Exception in ReadListener.onDataAvailable() may cause infinite loop
Change servlet error logging
Update to latest release of jastow
Add httponly to version 0 cookies
Implement Part.write
Make HTTP client handle failue to connect better
Add toString to header map
- replaces manual array copy with System.arraycopy
- removed useless creation of StringBuilder
Handle proxy timeout better
Handle connection close from a backend properly
Minor Javadoc