have flash augment the save load for nested save load modules

tweaks

tailored for decorating pytorch module methods

two more functions

module device

add ability to return unstacked tensors for pad_sequence, add a test with images of varying dimension

return pad lens for pad_sequence

fix safe_stack

fix masked mean

add safe stack and cat

shape with replace

copy paste in a decorator from another repo with cleanup and a test

preferred behavior

add another function

add masked mean, make it flexible, and then add a few padding and slicing functions