[#1785] Fix incorrect javadocs
Currently the system variable to chose which type of zlib decoder is being negated
HTTP Chunk, wrong delimiter written
[#1792] PlatformDependent.freeDirectBuffer(..) now respect hasUnsafe()
[#1788] Correctly decode CRC32 and ISIZE when using JdkZlibDecoder

Because of incorrect decoding a CompressionException was thrown before
Free up all buffers after the tests
[#1797] Throw IllegalArgumentException if AbstractByteBuf.skipBytes(...) is used with a negative value
[#1798] Correctly handle skipping of too big frames
No need to check instanceof everytime to find the next inbound / outbound context
Remove legancy code which we not need anymore as we use gathering writes anyway everywhere
@Deprecated ChannelOutboundHandler.deregister(...)
Add tests to try to track down some buffer issues
[#1797] No use internalNioBuffer() in derived buffers as it is not meant for concurrent access
Make sure only direct ByteBuffer are passed to the underlying jdk Channel.

This is needed because of otherwise the JDK itself will do an extra ByteBuffer copy with it's own pool implementation. Even worth it will be done
multiple times if the ByteBuffer is always only partial written. With this change the copy is done inside of netty using it's own allocator and
only be done one time in all cases.
[#1805] Fix example in javadocs of SimpleChannelInboundHandler
Split up the nioBuffers() method to allow for inline. Related to #1812

This move less common method patterns to extra methods and so make the nioBuffers() method with most common pattern (backed by one ByteBuffer) small enough for inlining.
Move encode of chunked content to an extra method, this allows for inline. Related to #1812

encode of chunked content is not the most common pattern so moving it to an extra method makes it possible to inline the rest as it is a smaller method now.
Ensure operationProgressed is invoked even on completion

- Fixes #1809
[maven-release-plugin] prepare for next development iteration
[maven-release-plugin] rollback the release of netty-4.0.9.Final