pictureviewer: free formathandlers in destructor

Origin commit data
------------------
Commit: 473f33e57f
Author: Stefan Seyfried <seife@tuxbox-git.slipkontur.de>
Date: 2013-04-14 (Sun, 14 Apr 2013)

src/driver/pictureviewer/pictureviewer.cpp

@@ -448,6 +448,12 @@ void CPictureViewer::Cleanup ()
 		free (m_CurrentPic_Buffer);
 		m_CurrentPic_Buffer = NULL;
 	}
+	CFormathandler *fh = fh_root;
+	while (fh) {
+		CFormathandler *tmp = fh->next;
+		free(fh);
+		fh = tmp;
+	}
 }
 
 void CPictureViewer::getSize(const char* name, int* width, int *height)