Use WebM in copyright notice for consistency

Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.

Fixes issue #97.

Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
diff --git a/libs.mk b/libs.mk
index 32f8a34..45cf9bf 100644
--- a/libs.mk
+++ b/libs.mk
@@ -1,5 +1,5 @@
 ##
-##  Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
+##  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 ##
 ##  Use of this source code is governed by a BSD-style license
 ##  that can be found in the LICENSE file in the root of the source