fixed warning caused by int hashcode not being declared as a getter in intx superclass.  Tests pass.
fixed warning caused by int hashcode not being declared as a getter in intx superclass.  Tests pass.

analogic/bson,mongo-dart/bson,sestegra/bson,mongo-dart/bson,vadimtsushko/bson,kaisellgren/bson,analogic/bson,sestegra/bson,vadimtsushko/bson