minor, split matlab gand_get_series() into 3 parts, gand_open(), gand_get_series() and gand_close()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/keepalive' into next

* feat/keepalive:
  minor, split matlab gand_get_series() into 3 parts, gand_open(), gand_get_series() and gand_close()
chore, remove temporary debugging output

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'next'

* next:
  chore, remove temporary debugging output
  chore, follow-up, also don't check for yacc and lex anymore
  major, kick old message command syntax
  minor, provide message type /raw? which utilises sendfile(3) to transmit the payload
  hygiene, don't pass on unused arguments to sub-routines
  hygiene, collapse the two cases GET_SER and GET_DAT
  minor, split matlab gand_get_series() into 3 parts, gand_open(), gand_get_series() and gand_close()