Added a lot of events relating to weather, including those for entities. Thanks wizjany!

src/main/java/org/bukkit/event/weather/WeatherChangeEvent.java

@@ -0,0 +1,50 @@
+package org.bukkit.event.weather;
+
+import org.bukkit.World;
+import org.bukkit.event.Cancellable;
+
+/**
+ * Stores data for weather changing in a world
+ */
+public class WeatherChangeEvent extends WeatherEvent implements Cancellable {
+
+    private boolean canceled;
+    private boolean to;
+    private World world;
+
+    public WeatherChangeEvent(World world, boolean to) {
+        super(Type.WEATHER_CHANGE, world);
+        this.world = world;
+        this.to = to;
+    }
+
+    /**
+     * Gets the cancellation state of this event. A canceled event will not
+     * be executed in the server, but will still pass to other plugins
+     *
+     * @return true if this event is canceled
+     */
+    public boolean isCancelled() {
+        return canceled;
+    }
+
+    /**
+     * Sets the cancellation state of this event. A canceled event will not
+     * be executed in the server, but will still pass to other plugins
+     *
+     * @param cancel true if you wish to cancel this event
+     */
+    public void setCancelled(boolean cancel) {
+        canceled = cancel;
+    }
+
+    /**
+     * Gets the state of weather that the world is being set to
+     *
+     * @return true if the weather is being set to raining, false otherwise
+     */
+    public boolean toWeatherState() {
+        return to;
+    }
+
+}