Add Equality,{,Not}Equal,Identical}Operation

* EqualityOperation – abstract superclass (does *not* quite correspond
  to RedHat’s EqualityOp because that doesn’t include IdentityOp)
* EqualOperation – RedHat’s EqualOp (==)
* NotEqualOperation – RedHat’s NotEqualOp (!=)
* IdenticalOperation – RedHat’s IdenticalOp (===)
Add tests for {Equality,{,Not}Equal,Identical}Operation