A fluent interface to apply a list of mixins to a superclass.

class X extends mix(Object).with(A, B, C) {}

The mixins are applied in order to the superclass, so the prototype chain will be: X->C'->B'->A'->Object.

This is purely a convenience function. The above example is equivalent to:

C = Mixin(C)
B = Mixin(B)
A = Mixin(A)
class X extends C(B(A(Object))) {}