Paratopic: Overdub patch notes & updates

Small patch today; an array of minor QoL tweaks and rough edges smoothed down. Next big update will be coming up end of week, bringing in achievements and (hopefully) the clearing out of our bug tracker!

Checkpoints are in the game! We hear that it's frustrating to hit a bug, or just... have to quit the game to go do something else... and end up losing a bunch of time. And we hate to see this spoiling people's enjoyment of our work.