This allows specifying how many times per second an effect should be
triggered for a particle source instead of triggering the effect every
frame. This will allow modders to achieve more consistent particle
effects regardless of FPS.
Nightmare discovered an off-by-one error when checking the validity of a
particle effect handle. Since the new ID system makes that much easier
and less error-prone I decided to go ahead and convert all handles to
an ID typedef which also fixes the reported bug.
This can be used for mark parts of the code which should be unreachable
in normal execution. In debug mode, if such a statement is reached an
Error dialog is shown which aborts the execution. In release mode the
macro is replaced with a compiler specific expression that lets the
compiler know that this part is unreachable which allows it to optimize
the code better.