DSB Version 0.19

[Sophia]

What's new:

- Allowed more than 4 classes, and more than 4 subskills per class
- Replaced "monster_hit_by_weapon" with more useful "monster_took_damage"
- Monsters can use "special_attack" property to call a function when damaging a character
- Grabbing portions of scaled images now won't introduce artifacts
- Wallsets can now be animated (and will actually work)
- Fixed a memory leak in attack methods
- Fixed a few minor rendering glitches