[atomix] Fix build error from last commit.

[Andre Klapper <aklapper src gnome org>]

commit ddbba33e7e0c908cc981e72227356526a14a5e46
Author: Andre Klapper <a9016009 gmx de>
Date:   Mon Mar 8 18:11:01 2010 +0100

    Fix build error from last commit.

 src/level.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/level.h b/src/level.h
index 22f89a9..f7ead9e 100644
--- a/src/level.h
+++ b/src/level.h
@@ -20,6 +20,8 @@
 #ifndef _ATOMIX_LEVEL_H 
 #define _ATOMIX_LEVEL_H 
 
+#include "playfield.h"
+
 #define LEVEL_TYPE        (level_get_type ())
 #define LEVEL(o)          (G_TYPE_CHECK_INSTANCE_CAST ((o), LEVEL_TYPE, Level))
 #define LEVEL_CLASS(k)    (G_TYPE_CHECK_CLASS_CAST((k), LEVEL_TYPE, LevelClass))