7DRL Day 3: Combat works

I'm happy enough with my combat system now, and I feel I'll be able to balance it effectively. The early game will focus on physical damage, and the late game will split between electric (tasers) and heat (laser) damage, with electric coming in a little earlier.

I removed strength from all damage calculations. Instead, strength affects fatigue, which maps approximately to how often you can use your weapon. If you get "exhausted" (75% fatigue) or "super exhausted" (90% fatigue), you lose 1 or 2 turns during which your reflex score is halved.

The changelog is too long to list, but here are the highlights:

• Many UI improvements; you can see all relevant stats in mouseovers and info screens
• Enemies pursue and attack the player with both melee and ranged weapons
• Ranged combat works, even if you're using the keyboard (tab to select, enter to fire)
• Discovered that Swift will JSONize a large 64-bit integer but not read it back again, so save files will occasionally zap the RNG for no reason, but at least it's recoverable