blood splatters and weapon flashes

[ozkriff]

This PR:

• Removes unneeded 0.1s pause from attack visualizer;
• Tweaks the colors of dust effect;
• Increases the minimum time of an arc more action;
• Adds weapon flashes of four types: slash, smash, pierce and claw;
• Adds directed dynamic blood splatters.

Demo:

Depends on ozkriff/zemeroth_assets_src@1f1813e

Closes #86
Closes #400