Add copyright headers to remaining gyp files.

gyp/effects.gyp

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 # Gyp file for effects
 {
   'targets': [
     {
       'target_name': 'effects',
       'product_name': 'skia_effects',
       'type': 'static_library',
       'standalone_static_library': 1,
       'dependencies': [
         'core.gyp:*',
@@ skipping 21 matching lines @@
         ['skia_gpu == 1', {
           'include_dirs': [
             '../include/gpu',
             '../src/gpu',
           ],
         }],
       ],
     },
   ],
 }