changed enum comparison to ==.

isDependentTo returns empty set rather than null

Mage/src/main/java/mage/constants/PhaseStep.java

@@ -1,5 +1,7 @@
 package mage.constants;
 
+import mage.game.turn.Phase;
+
 /**
  *
  * @author North
@@ -33,6 +35,14 @@ public enum PhaseStep {
         this.stepText = stepText;
     }
 
+    public boolean isBefore(PhaseStep other){
+        return this.getIndex()<other.getIndex();
+    }
+
+    public boolean isAfter(PhaseStep other){
+        return this.getIndex()>other.getIndex();
+    }
+
     public int getIndex() {
         return index;
     }