Includes various cosmetic changes and refactoring including
naming the sharp filters differently (since they are no longer
8-tap).
Change-Id: Ida5a19ca0daa9f6a64a6734394c685b2a4a2564a
BD-rate performance improvement (on top of ext-intra):
derflr 0.22%
hevclr 0.36%
hevcmr 0.48%
hevchr 0.37%
stdhd 0.19%
Average speed impact on some derf clips is about 40% slower (on
top of ext-intra). Speed improvment is a to-do.
Change-Id: I8fe3fe8c5e4f60d0462778adbcc15c84dfbe7a25
Under the experiment of EXT_REFS: LAST2_FRAME, LAST3_FRAME, and
LAST4_FRAME.
Coding efficiency: derflr +1.601%; hevchr +1.895%
Speed: Encoder slowed down by ~75%
Change-Id: Ifeee5f049c2c1f7cb29bc897622ef88897082ecf
