Tiny optimization
Reduce even more garbage by exposing ByteBuf.internalNioBuffer()
Move ReferenceCounted and AbstractReferenceCounted to io.netty.util

- Fixes #1441
- Also move and rename IllegalBufferAccessException to ReferenceCountException
- Prettier reference count exception messages
Suppress duplicate warning message printed when a message reaches at the end of pipeline
Fix memory leaks
ReferenceCountException -> IllegalReferenceCountException
Prefer direct buffer by default

- Because it's faster in most cases thanks to unsafe
Log correct system property name
Simplify hello world content generation
Remove the volatile modifiers where they are unnecessary
Fix test failures and reported leaks
Fix reported leaks
Upgrade dependencies
[maven-release-plugin] prepare release netty-4.0.0.CR4
[maven-release-plugin] prepare for next development iteration