NEW disp.dat file format that does not repeat the node IDs with each timestep
* disp.dat files are now ~25% smaller
* newer scripts can be used with older files by invoking the --legacynodes flag
* within the new version, CLI syntax shouldn't have to change
* new disp.day format is:
NUM_NODES
NUM_DIMS
NUM_TIMESTEPS
NODE IDs
for each timestep:
X-DISP
Y-DISP
Z-DISP