Added clamp of qindex to valid range

The qindex for a segment was not clamped in ABSDATA mode, which may
cause invalid memory access if an ill-formed stream has a negative
value in ABSDATA mode. This commit added clamp to make sure qindex
for a segment always fall into valid range.

Change-Id: I0a74d00f4ef40aec7edaeca1d03c8645e23ab08c
Merge "Added clamp of qindex to valid range"
added clamp of segment loop filter level

for ABSDATA mode, so segment loop filter level always fall in valid
range for both Absolute and delta modes.

Change-Id: If90df3411479533dbdab63f8ae088d2f5dd174a9
Adds an intermediate speed level for rtc

Moves the existing speed 6 to speed 7 and adds an
intermediate level 6 which is roughly in between
speeds 6 and 7 in both speed and coding efficiency.
Also includes some minor fixes/adjustments.

Change-Id: I98befc4d82d750e79fe426c457c4a2571f6b6cc7
Merge "Adds an intermediate speed level for rtc"
vpx_temporal_scalable_patterns: fix to encoding_bitrate computation.

Change-Id: I56fcb82c4334c7591b765b55b3c2912778af6db5