Merge remote branch 'origin/master' into experimental

Change-Id: I52f21ff6f9a1dca7099a8459657f6f288c5bfe40

diff --cc vp8/encoder/encodemb.c
Simple merge

diff --cc vp8/encoder/firstpass.c
Simple merge

diff --cc vp8/encoder/rdopt.c
Simple merge

diff --cc vpx/vp8cx.h
Simple merge