4-frame run added for Astronaut

Hello, we've now included an alternate 4-frame run for the astronaut in case you wish for the "hero" sprite to have a little extra fluidity. Users who have previously purchased this asset pack can simply re-download the zip file with the new frames included.

Both a run and a run-while-shooting are included. The alternate eye shape sprites for each are also included.

Please note that the frame count for these sprites is purposefully limited in keeping with the 1-bit style. This run cycle addition is intended solely for the astronaut; while we may add additional enemy sprites in the future, no increased frame counts for the existing sprites are planned.