Commonly-used helper functions

The following helper functions are commonly-used when preparing data and models for use with plenoptic.

remove_grad	Detach all parameters and buffers of model (in place).
set_seed	Set the seed.
load_images	Load in images.
to_numpy	Cast tensor to numpy in the most conservative way possible.
convert_float_to_int	Convert numpy array from float to 8 or 16 bit integer.