when we know that there were no errors or premature return

2. add sanity checks to color_apply_icc_profile : cmsSigRgbData

2. set rate of 1 equal to 0 - fixes bug with feasible truncation algo where a lossless encode with multiple layers was
not in fact lossless

for multi-layer rate control, set initial upper bound for next layer to be lower bound for current layer, minus one