The following functions were added to both IntegerBitSet and ArrayBitSet:
fn eql(self: Self, other: Self) bool
fn subsetOf(self: Self, other: Self) bool
fn supersetOf(self: Self, other: Self) bool
fn complement(self: Self) Self
fn unionWith(self: Self, other: Self) Self
fn intersectWith(self: Self, other: Self) Self
fn xorWith(self: Self, other: Self) Self
fn differenceWith(self: Self, other: Self) Self