Post-Game Jam builds

Now that Godot Wild Jam 72 is over, I'm putting up a (slightly) polished version of the game. This doesn't include any new features, but fixes a few things introduced very late in the process.

Things you will notice:

• The hurt animation plays correctly (gave up on doing it through the AnimatonTree/AnimationPlayer and went with a Tween).
• The start page now says "↻ New Random Seed"
• Stats more consistent.
• A working HTML5 build.

Under the hood (things you won't notice):

• Items refactored into a class instead of being unrelated scenes.
• Other code and documentation cleanup.