adds new sg sprites by Dongwaiver
adds flak jacket accessory for 3 points in misc category, you can wear it differently by using it in hand

citing Dongwaiver from initial PR

For reference, these are the 'new' sprites that're being added:

After its initial removal, the Power Pack's sprite has been reintegrated into the Combat Harness. I don't believe the Combat Harness was originally intended to be viewed without it, which is why it's much slimmer (and darkly-shaded in the center) than the standard M3 suits. Just to clarify, this is purely a visual change that's intended to restore the Smartgunner's chunkiness of yesteryear.

The jumpsuit-attachable flak jacket is a homage to Drake, who's seen rocking that very same fit in the movie. It's a very slightly modified version of the M70 that the pilots're seen wearing, trimmed down to seamlessly fit underneath the Combat Harness. While I originally imagined the flak jacket giving some extra defense to its wearer (via the same code that makes ceramic plates work), I don't mind if it remains a purely cosmetic accessory.

The greyish-green palette swap (originally reserved for an unused(?) variant of the officer's armored suit) works surprisingly well as a movie-accurate representation of the Combat Harness. I think it's got a lot of potential, though it's something that could be explored in a later pull request.