libvpx: Support the vp9 extended profiles

Bump the minimum libvpx version to 1.3.0 and rework the configure logic
to fail only if no decoders and encoders are found.

Based on the original patch from Vittorio.

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>