INT-2936 Fix TCP Binary DeSerialization with NIO

Inadvertent sign extension on binary data with bit 7 set
causes early termination of binary deserializers.

The ChannelInputStream (which replaced the piped input
and output streams) failed to mask off the top 24 bits
of "normal" bytes received, causing Deserializers to
believe the stream was closed.

Add a mask of 0xff to bytes read.

Add a test case.
Merge pull request #749 from garyrussell/INT-2936

* INT-2936: Fix TCP Binary DeSerialization with NIO