Fix StackOverflowError in LocalEcho.doBeginRead() when the peer channel keeps writing data

- Fixes #1380
Some optimizations to the http codec
Only call key.interestedOps() if needed
Make sure that setAutoRead(false) has a direct effect and only update interestedOps if needed
No need to clear buffer as it is cleared later anyway and only update interestedOps if needed
No need to create temporary arrays
[#1392] Fix bug where SslHandler returned wrong value for getCloseNotifyTimeoutMillis()
Re-add Unsafe.voidPromise() which can be used for Unsafe operations for which no notification should be done [#1375]