fix ordering of constraint files: first the default board.xdc, than any from board.json, then from the command line
fix ordering of constraint files: first the default board.xdc, than any from board.json, then from the command line

hanw/connectal,cambridgehackers/connectal,chenm001/connectal,chenm001/connectal,cambridgehackers/connectal,8l/connectal,csail-csg/connectal,csail-csg/connectal,hanw/connectal,chenm001/connectal,8l/connectal,csail-csg/connectal,chenm001/connectal,cambridgehackers/connectal,hanw/connectal,cambridgehackers/connectal,csail-csg/connectal,csail-csg/connectal,chenm001/connectal,8l/connectal,8l/connectal,hanw/connectal,8l/connectal,cambridgehackers/connectal,hanw/connectal