Initial work on support for objects whose images span multiple tiles.

Made TileSet an interface.  Throw exceptions for unknown tile or tile
set requests.  General clean-up and documentation.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@427 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/media/tile/TileException.java

@@ -0,0 +1,15 @@
+//
+// $Id: TileException.java,v 1.1 2001/10/11 00:41:26 shaper Exp $
+
+package com.threerings.media.tile;
+
+/**
+ * Thrown when an error occurs while working with tiles.
+ */
+public class TileException extends Exception
+{
+    public TileException (String message)
+    {
+	super(message);
+    }
+}