Disentangle asteroids changes

[mrwonko]

The 2013 JA source release includes changes from the asteroids mod that Raven was connected to, including breaking ones to the death method enum. Compare that with the 2003 mod sdk and fix the regressions.

[mrwonko]

There's a similar thing in JK2, but reversed: the official mod SDK was from in-between 1.02 and 1.04. That's less problematic for retaining vanilla compatibility, but maybe someone cares about mod SDK parity?