[#879] Notify correct ChannelFuture for queued FileRegions
[#880] correctly use methods which take a ChannelFuture as parameter
Read only when requested (read-on-demand)

This pull request introduces a new operation called read() that replaces the existing inbound traffic control method. EventLoop now performs socket reads only when the read() operation has been issued. Once the requested read() operation is actually performed, EventLoop triggers an inboundBufferSuspended event that tells the handlers that the requested read() operation has been performed and the inbound traffic has been suspended again. A handler can decide to continue reading or not.

Unlike other outbound operations, read() does not use ChannelFuture at all to avoid GC cost. If there's a good reason to create a new future per read at the GC cost, I'll change this.

This pull request consequently removes the readable property in ChannelHandlerContext, which means how the traffic control works changed significantly.

This pull request also adds a new configuration property ChannelOption.AUTO_READ whose default value is true. If true, Netty will call ctx.read() for you. If you need a close control over when read() is called, you can set it to false.

Another interesting fact is that non-terminal handlers do not really need to call read() at all. Only the last inbound handler will have to call it, and that's just enough. Actually, you don't even need to call it at the last handler in most cases because of the ChannelOption.AUTO_READ mentioned above.

There's no serious backward compatibility issue. If the compiler complains your handler does not implement the read() method, add the following:

public void read(ChannelHandlerContext ctx) throws Exception {
    ctx.read();
}

Note that this pull request certainly makes bounded inbound buffer support very easy, but itself does not add the bounded inbound buffer support.
[#873] [#868] Split ChannelFuture into ChannelFuture and ChannelPromise
Remove ChannelFutureProgressListener
Fix a bug in AioSocketChannel where recursive doBeginRead() is allowed unexpectedly
Add new ChanelFuureListener impl that mimic the old behavior of Netty 3 and so allow to also call fireException for outbound operations
Fix a bug in AioSocketChannel where inboundBufferSuspended() is triggered even if the channel is closed.
Fix a bug in NIO transport where inboundBufferSuspended() is triggered even if the channel is closed.

- No non-static wildcard import
Move utility method to abstract base class and correctly handle expand of buffer also for OIO
Extract the utility classes related with SSL to the util package
Fix a bug where SslHandler does not respect the startTls flag

- Fixes #856
- Add a dedicated test case: SocketStartTlsTest
Do not set 'Content-Encoding' if the target encoding is 'identity'

- Fixes #769
Make ChannelConfig.setAutoRead() triggers Channel.read() if autoRead was previously false

- also rename JDK socket and channel variables so that they are less ambiguous
Do not auto-start read operation
Revert 5161ca733c330e21fa0f1b89ba4d464791600d52
Re-ignore ServerSocketSuspendTest (unignored by mistake)
[#887] [#866] [#883] Add unified interface for Message oriented protocols and also use direct buffers for them
[#884] Split SCTP transport into extra module
Make sure the Unpooled.EMTPY_BUFFER can not be freed and the capacity can not be changed