Add more set.mm theorems to mmil
Add more set.mm theorems to mmil

This is in the list of set.mm theorems which don't exist in
iset.mm. The ones being added are logic theorems of the usual
sort (DeMorgan's law and the like).

iman , annim , oran , alex , exnal , alexn , exanali , 19.36 ,
19.37 , and exmo are the set.mm theorems and the iset.mm
similar theorems are imanim , annimim , oranim , alexim ,
exnalim , alexnim , exanaliim , 19.36-1 , 19.37-1 , and
exmonim , respectively.

metamath/set.mm,metamath/set.mm,metamath/set.mm