Restructured Mage module

Mage/src/main/java/mage/abilities/MageSingleton.java

@@ -0,0 +1,19 @@
+package mage.abilities;
+
+/**
+ * Marker class for singleton abilities and effects.
+ * Prevents effects and abilities to get new Id across the games on the server.
+ * Can be used only for stateless effects and abilities. (e.g. no Duration)
+ *
+ * Intended to be used to avoid bugs and for performance reasons.
+ *
+ * "Must" be used for abilities that use getId() as compare parameter like:
+ * FlyingAbility.getInstance().getId()
+ * in
+ * permanent.getAbilities().containsKey(FlyingAbility.getInstance().getId())
+ *
+ *
+ * @author noxx
+ */
+public interface MageSingleton {
+}