Fix generic/conventional vertex array glitches.

Fix generic/conventional vertex array glitches.
Changed _NEW_ARRAY_ATTRIB_0 back to 0x10000 so that the conventional and
generic enable bits do not alias.
In ac_import.c test Array.Normal.Enabled instead of Array._Enabled & _NEW_ARRAY_COLOR0, etc.
In t_array_import.c give priority for generic arrays over conventional
arrays on an individual basis, not all or none.