savescumming acheivement

[Norgg]

We could track this by having the last seed you died in saved, so if someone reloads that file immediately they've almost certainly save scummed.

"Scum of the Earth" or "Scum of the sphere" for the title maybe?

[Riot]

adding savescumming detector and steam achievement, check new seeds for collision with savescum seeds to prevent false positives - resolves #375

→ <<cset 818ad2c074b6>>

[Riot]

new achievement for completing the game without savescumming, resolves #375

→ <<cset 4391542a53d3>>