Stats can track a variety of things about the game, and are stored in the save.
The options menu lets you reconfigure things like your name and species.

This also introduces fields for your name and species, but they cannot be
configured just yet

This commit also adds a template for such news and makes
news item pop up more frequently

The "free X" powerups now only appear if you have at least one of the item, and also stop appearing once you have 100

Before, each one multiplied the time between spawns by 0.5
Now, they multiply the time by 0.75, then 0.78, then 0.81,
and so forth

This is needed to make sure that all of the buttons get updated - some will
have stale states, otherwise

The last state of the upgrade buttons are now cached. This ensures that
the classList is perturbed *only* if this would actually change the
appearance, and seems to be far faster than just adding something
to the classList over and over