Set on all 16x16 intra/inter modes

Features:
- Butterfly fDCT/iDCT
- Loop filter does not filter internal edges with 16x16
- Optimize coefficient function
- Update coefficient probability function
- RD
- Entropy stats
- 16x16 is a config option

Have not tested with experiments.

hd:     2.60%
std-hd: 2.43%
yt:     1.32%
derf:   0.60%

Change-Id: I96fb090517c30c5da84bad4fae602c3ec0c58b1c

Also factorize ACMRandom to acm_random.h.

Change-Id: I3b6eeb36fcbf7ae6dd3d2892bc40348f5c17982b

Also fix unit testing.

Change-Id: Iacdc6f1ec53388e093cda1c13e4379e83d4a6535

Change-Id: I27c98025b2857e2911005a52dd57c46e2524e815