chore, PEBKAC, include config.h in gand_get_series.c
chore, do the #include {octave/mex.h,mex.h} dance in gand_handle.h
Merge branch 'core/matapi'

* core/matapi:
  chore, do the #include {octave/mex.h,mex.h} dance in gand_handle.h
  chore, PEBKAC, include config.h in gand_get_series.c