use SDL2 as ifdef symbol because we're not really sdl1.3 compatible, change the compatibility layer, drop unused code, add some documentation
engine uses final (?) SDL 2 APIs, new events and types added. Touch input broke by the way, and system events should be handled differently
engine compiles for ios again, but SDL bindings are outdated. Fix some warnings
bug #668 + reorder conditions for kick slightly, to call the math last
Fix spectator desync in rare conditions (there was team which left during its turn, and last command with timestamp from it was '+')