fix: constrained intra
vui: emit VUI w/ timing info unconditionally, remove timing info from VPS

Since many tools seem to only look in the VUI for timing info, it seems to be
best to output that info there, and remove it from the VPS (to avoid sending
redundant data in our headers)
fix: rdLevel <= 1
vbv: clear row diagonal and cu SATD costs after vbv row reset was triggered

refs #45
cli: help nits (closes #47)