ported fixes from M4 aggr.mx handle void,void groups/attributes group.mx use keyedness
ported fixes from M4
aggr.mx handle void,void groups/attributes
group.mx use keyedness

tablet.mx fix compilation (variable first not used)

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb