Made speed of most of battle animations time-based

- 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.

git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3438 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834