If the requested extension could not be loaded, but was optional, don't add a null to the return collection or an NPE will result
Detect if the netty libraries are there and not load teh dest factory if they aren't.   Mark it optional.
Maintain the order that extensions are discovered/added and use that order when searching to allow some level of predictability and controlability.
Remove the netty libs from lib (but keep the CXF plugins which should now be properly optional based on presense of netty libs).  Need to make sure Netty transport is not picked up by default due to issues.
Make sure the netty client is optional can can not cause failures if netty isn't found
[CXF-4242] Adjust how the exception is output in the stack trace as well as how it's created on the client.
Fixes the failing tests