Adds a new StargateTeleportEvent to combine some duplicated code

src/main/java/net/knarcraft/stargate/event/StargateTeleportEvent.java

@@ -0,0 +1,18 @@
+package net.knarcraft.stargate.event;
+
+import org.bukkit.Location;
+import org.bukkit.event.Cancellable;
+
+/**
+ * A generic teleportation event
+ */
+public interface StargateTeleportEvent extends Cancellable {
+
+    /**
+     * Return the location of the players exit point
+     *
+     * @return <p>Location of the exit point</p>
+     */
+    Location getExit();
+
+}