this should improve consistency of mortar cluster spread and snowball knocks

fix bug that locked unlocked campaign missions, see issue #452

fix nil comparison error, see issues 470 and 601

this is fairer

Use tr() properly

This is something we need to check in all translations. Occasionally the source phrase ends w/ a space. Need to make sure translations take this into account.

So. First pass. Add secondary explosions to RateExplosion and RateShotgun. Not yet added to shoves. This is of limited utility at present since the dX has to be small since we can't bother tracing all hog motion. But, should be more useful once shove is added, and tracking of explosives and mines.