fixes most of blit order-related bugs in battles (#1200, #1238, #226)
known issues, will fix soon:
- there are still some minor blitting issues during movement
- destruction of walls in siege is out of sync with catapult projectile movement
- speed of creature-related animation no longer depends on framerate
- most of values from cranim.txt are now used correctly
- removed BMPPalette struct in favor of SDL_Color
- animation group "DEAD" that is used to display dead stacks, by default consists from last frame of "DEATH" group
Notes:
- animation speed may still need some adjustments
- range of config property "battle/animationSpeed" has been changed. This may result in extremely fast animation. To fix - change animation speed via options.
