Merge pull request #16 from mastodon-sc/fix-undoredostack-clear

Tiny change to fix UndoRedoStack.clear()

Author: tinevez

src/main/java/org/mastodon/undo/UndoRedoStack.java

@@ -183,6 +183,8 @@ public void trim()
 	public void clear()
 	{
 		stack.clear();
+		end = 0;
+		top = 0;
 	}
 
 	/**