Add UpToDuality command for lists

[CunningGabe]

UpToDuality(L) would return a new list such that if M is in L, then Dual(M) is not in L. e.g... `gap> UpToDuality(Cube(3), Simplex(3), CrossPolytope(3));

[Cube(3), Simplex(3)] `

[CunningGabe]

Done in 75ae6d4e6678ac658d28f254890735146a4f5dd2.