Enforce Weapon Pitch Limits + Fix Weapon "Unlatching"

[DARwins1]

Prevents weapon muzzles from being angled beyond what it specified in a weapon's stats (via minElevation and maxElevation) when firing. Also (as well as the real main motive for this PR), the minElevation and maxElevation stats of the Seraph Missile Array (and similar weapons) have been set to 0. This prevents the missile/rocket tubes of the weapon magically "unlatching" when the weapon aims upward.

Here's a comparison of what this looks like versus an unmodified version of the weapon:

The Heavy Rocket Array and Angel Missile (Campaign) have also received this change. This shouldn't affect other weapons in a noticeable way.