Implemented LZ4 compression codec

Motivation:

LZ4 compression codec provides sending and receiving data encoded by very fast LZ4 algorithm.

Modifications:

- Added `lz4` library which implements LZ4 algorithm.
- Implemented Lz4FramedEncoder which extends MessageToByteEncoder and provides compression of outgoing messages.
- Added tests to verify the Lz4FramedEncoder and how it can compress data for the next uncompression using the original library.
- Implemented Lz4FramedDecoder which extends ByteToMessageDecoder and provides uncompression of incoming messages.
- Added tests to verify the Lz4FramedDecoder and how it can uncompress data after compression using the original library.
- Added integration tests for Lz4FramedEncoder/Decoder.

Result:

Full LZ4 compression codec which can compress/uncompress data using LZ4 algorithm.
Rename SnappyFramedEncoder/Decoder to SnappyFrameEncoder/Decoder

Related issue: #2766

Motivation:

Forgot to rename them before the final release by mistake.

Modifications:

Rename the classes

Result:

Better naming
Reduce the fallback SOMAXCONN value

Related issue: #2407

Motivation:

The current fallback SOMAXCONN value is 3072.  It is way too large
comparing to the default SOMAXCONN value of popular OSes.

Modifications:

Decrease the fallback SOMAXCONN value to 128 or 200 depending on the
current OS

Result:

Saner fallback value
Add socksx package which supports SOCKS 4/4a/5

Motivation:

SOCKS 4 and 5 are very different protocols although they share the same
name.  It is not possible to incorporate the two protocol versions into
a single package.

Modifications:

- Add a new package called 'socksx' to supercede 'socks' package.
- Add SOCKS 4/4a support to the 'socksx' package

Result:

codec-socks now supports all SOCKS versions
Overall clean-up on socksx package

- SocksV[45] -> Socks[45]
- Make encodeAsByteBuf package private with some hassle
- Split SocksMessageEncoder into Socks4MessageEncoder and
  Socks5MessageEncoder, and remove the original
- Remove lazy singleton instantiation; we don't need it.
- Remove the deprecated methods
- Fix Javadoc errors
Allow ChunkedInput to provide the progress of its transfer

Related issue: #2741 and #2151

Motivation:

There is no way for ChunkedWriteHandler to know the progress of the
transfer of a ChannelInput. Therefore, ChannelProgressiveFutureListener
cannot get exact information about the progress of the transfer.

If you add a few methods that optionally provides the transfer progress
to ChannelInput, it becomes possible for ChunkedWriteHandler to notify
ChannelProgressiveFutureListeners.

If the input has no definite length, we can still use the progress so
far, and consider the length of the input as 'undefined'.

Modifications:

- Add ChunkedInput.progress() and ChunkedInput.length()
- Modify ChunkedWriteHandler to use progress() and length() to notify
  the transfer progress

Result:

ChunkedWriteHandler now notifies ChannelProgressiveFutureListener.
[#2769] Fix regression when writing different message types

Motivation:

Due a regression NioSocketChannel.doWrite(...) will throw a ClassCastException if you do something like:

channel.write(bytebuf);
channel.write(fileregion);
channel.flush();

Modifications:

Correctly handle writing of different message types by using the correct message count while loop over them.

Result:

No more ClassCastException
[#2771] Correctly handle constructing of EmbeddedChannel

Motivation:

Because of an incorrect logic in teh EmbeddedChannel constructor it is not possible to use EmbeddedChannel with a ChannelInitializer as constructor argument. This is because it adds the internal LastInboundHandler to its ChannelPipeline before it register itself to the EventLoop.

Modifications:

First register self to EventLoop before add LastInboundHandler to the ChannelPipeline.

Result:

It's now possible to use EmbeddedChannel with ChannelInitializer.
Fix the regression caused by f31c630c8cc15c4de1cc7e45b6c5c8053d5bcb75

f31c630c8cc15c4de1cc7e45b6c5c8053d5bcb75 was causing
SocketGatheringWriteTest to fail because it does not take the case where
an empty buffer exists in a gathering write.

When there is an empty buffer in a gathering write, the number of
buffers returned by ChannelOutboundBuffer.nioBuffer() and the actual
number of write attemps can differ.

To remove the write requests correctly, a byte transport must use
ChannelOutboundBuffer.removeBytes()
Fix a bug where ChannelOutboundBuffer.removeBytes() throws ClassCastException

When a ChannelOutboundBuffer contains ByteBufs followed by a FileRegion,
removeBytes() will fail with a ClassCastException.  It should break the
loop instead.
Fix for issue #2765 relative to unstable trafficshaping test procedure

Motivation:

The test procedure is unstable due to not enough precise timestamping
during the check.

Modifications:

Reducing the test cases and cibling "stable" test ("timestamp-able")
bring more stability to the tests.

Result:

Tests for TrafficShapingHandler seem more stable (whatever using JVM 6,
7 or 8).
Fix checkstyle
Update TrafficShapingHandlerTest for Master

Motivation:
Test seems not yet stable (20ms instead of 40ms), so this small fix provides a "lightest" check.
If this is not passing again in master, one could deactivate this test by commenting the assertTrue in line 431.

Modification:
Divide by 2 the to be compared elapse time.

Result:
Locally this test is now passing.
Better fix for TrafficShapingHandlerTest

Motivation:
It seems that in certain conditions, the write back from the server is so quick that the handler has no time to compute traffic shaping. So 10ms of wait before acknowledging is added in server side.

Modifications:
Add 10ms waiting before server ackonwledge the client.

Result:
The timing is now suppsed to be stable.
Better fix for TrafficShapingHandlerTest

Motivation:
The test procedure is unstable when testing quick time (factor less or equal to 1). Changing to default 10ms in this case will force time to be correct and time to be checked only when factor is >= 2.

Modifications:
When factor is <= 1, minimalWaitBetween is 10ms

Result:
Hoping this version is finally stable.
Support IPv4 default route in ipfilter.

Motivation:

In GitHub issue #2767 a bug was reported that the IPv4
default route leads to the ipfilter package denying
instead of accepting all addresses.

While the issue was reported for Netty 3.9, this bug
also applies to Netty 4 and higher.

Modifications:

When computing the subnet address from the CIDR prefix,
correctly handle the case where the prefix is set to zero.

Result:

Ipfilter accepts all addresses when passed the
IPv4 default route.
Document the correct default value of SOMAXCONN

Motivation:

Recently we changed the default value of SOMAXCONN that is used when we can not determine it by reading /proc/sys/net/core/somaxconn. While doing this we missed to update the javadocs to reflect the new default value that is used.

Modifications:

List correct default value in the javadocs of SOMAXCONN.

Result:

Correct javadocs.
Fix example for Http Upload

Motivation:
The example mis handle two elements:
1) Last message is a LastHttpContent and is not taken into account by
the server handler
2) The client makes a sync on last write (chunked) but there is no flush
before, therefore the sync is waiting forever.

Modifications:
1) Take into account the message LastHttpContent in simple Get.
2) Removes sync but add flush for each post and multipost parts

Results:
Example is no more blocked after get test.

Should be done also in 4.0 and Master (similar changes)
Upgrading to HTTP/2 draft 14 framing

Motivation:

HTTP/2 draft 14 came out a couple of weeks ago and we need to keep up
with the spec.

Modifications:

- Removed use of segment throughout.
- Added new setting for MAX_FRAME_SIZE. Used by the frame reader/writer
rather than a constant.
- Added new setting for MAX_HEADER_LIST_SIZE. This is currently unused.
- Expanded the header size to 9 bytes. The frame length field is now 3
bytes and added logic for checking that it falls within the valid range.

Result:

Netty will support HTTP/2 draft 14 framing. There will still be some
work to do to be compliant with the HTTP adaptation layer.
Add HTTP/2 codec to netty-all maven dependency Motivation:

The HTTP/2 codec is missing from the netty-all maven dependency.
This means third party libraries have to pull in additional dependencies
above netty-all to use this codec.

Modifications:

Add HTTP/2 codec to netty-all

Result:

Third party libraries don't need to pull in additional dependencies
to use HTTP/2 codec.