Fix test failures in SingleThreadEventLoopTest on Windows

- It seems like Windows sometimes sleeps less than specified.
- Related issue: #726
Disable AIO transport tests on Windows

- Related: #726
Upgrade to netty-build-16
Rename the artifact 'netty' to 'netty-all' and make it non-OSGi

- We are going to make individual modules OSGi
Make sure the inbound/outbound buffer of the ChannelHandlerContext is only modified within the EventLoop