Extended ROI struct suitable for VP9.
ROI input from user is passed into internal struct and applied on every frame
(except key frame).

Enabled usage of all 4 VP9 segment features (delta_qp, delta_lf, skip,
ref_frame) via the ROI map input.
Made changes to nonrd_pickmode for the ref_frame feature.

Only works for realtime speed >= 5.
AQ_MODE needs to be turned off for ROI to take effect.

Change example in the sample encoder: vpx_temporal_svc_encoder.c to be suitable
for VP9.
Add datarate test.

Bump up ABI version.

BUG=webm:1470

Change-Id: I663b8c89862328646f4cc6119752b66efc5dc9ac