For the vp8 simulcast/multi-res-encoder:
Add flags to keep track of the disabling/skipping of
streams for the multi-res-encoder. And if the lower spatial
stream is skipped for a given stream, disable the motion
vector reuse for that stream.
Also remove the condition of forcing same frame type
across all streams.
This fix allows for the skipping/disabling of the base
or middle layer streams.
Change-Id: Idfa94b32b6d2256932f6602cde19579b8e50a8bd
9debbc2ec7