fix bug with get_times in noise scheduler

line up cross attention settings as in paper, customizable across layers

convenience class for SR unets in latter two stages in cascade

0.0.34

final preparation for continuous times, remove an unnecessary clip_de…

…noised hparam. always clipping on sampling, as it is an established necessary component of ddpm now

0.0.32

take a tiny step towards continuous times

it seems like all the conditioning is done in one block at the beginn…

…ing (if the paper diagrams are accurate), free up resnet blocks from conditioning (but add back the option later)

0.0.29

make self-attention line up and configurable as in the paper