Make EqClassOf a universal trait

Author: odersky

src/scala/EqClassOf.scala

@@ -3,5 +3,5 @@ package scala
 /** A class providing a specialized notion of equality, allowing
  *  only values in the same equality class to be compared.
  */
-trait EqClassOf[-T] extends EqClass
+trait EqClassOf[-T] extends Any with EqClass