Added chunk, world and block interfaces

src/org/bukkit/Chunk.java

@@ -0,0 +1,23 @@
+
+package org.bukkit;
+
+/**
+ * Represents a chunk of blocks
+ */
+public interface Chunk {
+
+    /**
+     * Gets the X-coordinate of this chunk
+     *
+     * @return X-coordinate
+     */
+    int getX();
+
+    /**
+     * Gets the Z-coordinate of this chunk
+     *
+     * @return Z-coordinate
+     */
+    int getZ();
+
+}