libvpx v1.10.0 Ruddy Duck Release Candidate 2

Added CHANGELOG
Updated AUTHORS
Bumped up library versions
Prepare for v1.10.0 release.

Update CHANGELOG, AUTHORS, README, libs.mk

Bug: webm:1712
Change-Id: Ic99de12b91a92c32f8a9485dcb759c48bc3eccd6
5 files changed