fix: buy: bots never buy enough ammo for secondary weapons
fix: yb_pickup_best disabling all pickups instead of weapons only
add: yb_pickup_ammo_and_kits, that allows to enable ammos medkits and kevlars
refactor: switched to crlib strings where possible
refactor: fix some compiler warnings at high levels
refactor: move constants to separate header (thx @spodlesniy)
