Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
vp8_update_gf_useage_maps() is only used by the encoder. This patch
fixes the ability to build in decode-only or encode-only
configurations.
Change-Id: I3a5211428e539886ba998e09e8abd747ac55c9aa