reset TUs on stage 2 of missions

and reduce copypasta
fix melee

getCurrentAction() only works for player actions.
initialize that variable at once!
firing & walking adjustments

Projectile: increase accuracy
TileEngine: don't refresh FoV unless RMB opens door
UnitWalkBState: let think()->Status_Standing->visForUnits() do the work
	if not RMB.
Merge branch 'master' of https://github.com/SupSuper/OpenXcom into oXc_kL

Conflicts:
	src/Battlescape/BattlescapeGenerator.cpp
	src/Battlescape/ExplosionBState.cpp
	src/Battlescape/ExplosionBState.h