Modified ULX/ULib bridge

> Made sure the code runs only when it has to, accounting all
possibilities - missing RelC, RelC not loaded yet, etc.;
> Made code quicker by localizing functions and using a more appropriate
loop;
> Modified descriptions to be more, uh... descriptive;
> Moved the ULX module file to be serverside only - it's not required on
the client - all the functions/hooks are serverside anyway.