Shoretrooper (Sean Fields) Backpack Vent Fix

A huge thanks to Sean Fields who made these files originally and gave them for FREE to the community! They're truly amazing. Some new images have surfaced since he did these files, so I've updated a couple of them to be more in accordance with the movie-used costumes.

These files fix the backpack vents.

To use less material when printing, I split the models each in half on the Z-axis.