Fix and clearify javadocs

Motivation:

ByteToMessageDecoder and ReplayingDecoder have incorrect javadocs in some places.

Modifications:

Fix incorrect javadocs for both classes.

Result:

Correct javadocs for both classes
Rename FastLzFramed* to FastLzFrame*
Fix class description of FastLzFrameDecoder
[#2768] Correctly duplicate buffer for CloseWebSocketFrames

Motivation:

The _0XFF_0X00 buffer is not duplicated and empty after the first usage preventing the connection close to happen on subsequent close frames.

Modifications:

Correctly duplicate the buffer.

Result:

Multiple CloseWebSocketFrames are handled correctly.