extended keybind mechanics a little. now any command can have any number of keys bound (except the movement commands: they are hardcoded for now

, and it is possible to bind F1-F10 and Tab, with optional modifiers. so keyboard help is F1 now, and minimaps are Tab and Shift+Tab.
also, "Press <KEY> for a list of commands" is not hardcoded now: the game knows which key to press, and shows it.
there is no way to rebind commands in-game, but "k8ivan_keys.rc" file is editable. it is written on the first start, and can be deleted to restore default keybindings.
movement keys should be editable too, and it should be possible to bind commands to Alt+<char> and Ctrl+<char>. maybe i'll implement it later.