Do not add to the headers for the pch the includes in the payload
Associate to autoParse entries only the payload (ROOT-6321)

de facto implementing lazy payload parsing instead of header
parsing on demand.
Improve autoparsing procedure

o Do autoload on autoparse and not viceversa
o Do not parse headers at module registration but rather the payload
  if not in lazy payload parsing mode
o Add a barrier not to re-parse payloads: fatal in presence of Aclic
libs or various missing include guards
Make sure that the list of bases is complete.