Remove the old include support.
stream: no longer process STREAM_GAP smsgs

StreamSmgs are used for raw stream reassembly only. They could also
be used to tell the rest of the engine about sequence gaps. This was
a left over from the older implementation, where the app layer used
the smsgs as well.
stream: remove unused gap structure from StreamMsg.
stream msg: remove structure
stream: pass TcpSession to StreamTcpReassembleProcessAppLayer

Preparation for removing flow pointer from StreamMsg. Instead of
getting the ssn indirectly through StreamMsg->flow, we pass it
directly as all callers have it already.
stream: remove flow reference from StreamMsg

StreamMsg' flow reference was used mostly to make sure a flow would
not get removed from the hash before inspection. For this it needed
to reference the flow use_cnt reference counter. Nowadays we have
more advanced flow timeout handling. This will make sure that if
there still are pending smsgs' in a flow, these will still be
processed.
stream: remove per thread queue for stream msgs

StreamMsgs would be stored in a per thread queue before being
attached to the tcp ssn. This is unnecessary, so this patch
removes this queue and puts the smsgs into the ssn directly.

Large patch as it affects a lot of tests.
stream: remove flags from StreamMsg
stream: increase max StreamMsg data

Increase from 4024 bytes to 4072 to make the whole structure
4096 again.
stream: don't send empty streammsg at stream end

No longer send an empty StreamMsg through the engine on stream end,
the messages were ignored anyway.