TODO

#TRY to keep the list in order
    * server
        ** support abilities
        ** generate player position _on game start_
        ** don't change map when impact position outside map
        ** fix invalid memory reads (shot_update_map)
           when impact pos close to edge
        ** fix shooting (when angle is close to 0°, 90°, 180°) (+ friendly fire)
        ** switch to using getaddrinfo for parsing IP, …
        ** end-game statistics
        ** make tanks not just 1 point on the map + detect collisions with them
        ** update tank's position when new round starts
    * client
        ** statistics in end-game screen
        ** on-screen keyboard (for touch capable devices)
        ** change map (and everything else) gradually
        ** fix end-game screen bug (corruption of memory: players array)
    * dyn_arr
        ** change allocated size in chunks
    * common
        ** write documentation (gameplay, usage, syntax, …)
        ** do not create .debug files when compiled without _DEBUG
    * abilities
        ** gather ideas for weaponry and abilities.
        ** document every weapon and ability.
        ** read abilities.conf
        ** write code for every ability in server_abilities 
    * later
        ** port to PSP
        ** support multiple games
        ** test under different compilers
        ** replace GCC-specific feature usage with other methods
            *** nested functions (GCC extension)
            *** anonymous structs/unions (GCC / C11)