Merge "Tie the bit cost scale to a define."

diff --cc vp9/encoder/vp9_encodemb.c
Simple merge

diff --cc vp9/encoder/vp9_encodemv.c
Simple merge

diff --cc vp9/encoder/vp9_pickmode.c
Simple merge

diff --cc vp9/encoder/vp9_rd.c
Simple merge

diff --cc vp9/encoder/vp9_rdopt.c
Simple merge