[MAJOR] kill CL_STINSPECT and CL_STHEADERS (step 1)

[MAJOR] kill CL_STINSPECT and CL_STHEADERS (step 1)

This is a first attempt at separating data processing from the
TCP state machine. Those two states have been replaced with flags
in the session indicating what needs to be analyzed. The corresponding
code is still called before and in lieu of TCP states.

Next change should get rid of the specific SV_STANALYZE which is in
fact a client state.

Then next change should consist in making it possible to analyze
TCP contents while being in CL_STDATA (or CL_STSHUT*).