Another round of minor changes and fixes for Bullet Fest.

Changes:

• Player damage feedback flashes made more prominent.

• Added red overlay that slowly fades in as player's health nears zero.

• Player sprite flashes when taking damage (blue for shield, red for health).

• Bleed bar effects added to player health and shield HUD.

• Corruption bar added to player health HUD.

• Particles added to player corruption HUD icon.

Bugfixes:

• Fix crash when madness expiry disconnects from a target that was recently removed.

• Fix explosion-based AOEs not damaging all mobs in the explosion radius.

• Fix rare case where movement input sticks in one direction.

• Fix multiple rare issues where previewing dice glitches the game.