switch races for underwater misssions

hopefully the _UNDERWATER string is obscure enough to avoid causing any
compatibility issues.
fix builder error?
revert range limits on psi

requires too much effort to get it working properly, max range was never
intended to work with that anyway.
fix some things.

potential memory leak
ammo loading
soldiers taking useless ammo
insanity in debriefing

new battle mode now only adds items assigned to the craft in base defenses
(including HWPs)
fix TU thing a little better.

can't do a std::max(1) when 0 is actually valid, better to fix it in the
reaction code
leftWeapon also should be loaded
small adjustment to panic mode
Merge pull request #956 from redv/fix_fixed_weapon3

Fix: leftWeapon also should be loaded.
fix interceptor and firestorm RMPs

turns out these were just copies of the skyranger and lightning RMPs, and
contained a bunch of invalid data, like nodes outside the map border,
causing the nodes vector to freak the heck out.
consistency
Merge branch 'master' of https://github.com/SupSuper/OpenXcom
add vapor colour to items
add vapor density to items
pass vapor info to projectile
add particle object
store a list of particles in the tile
have the projectile add particle effects as it moves
add square function to fmath
add transparency lookup tables for particle effects
cache a LUT pointer in the map