Update 8.1.5

ADD: Vickers 6-Ton Type A, Vickers 6-Ton Mark F (by cjprince)
ADD: If player withdraws from a zone with a Rescue objective, that objective is failed
CNG: Updated portraits by cjprince
CNG: Fog dissipation check now occurs every weather update cycle; lighter cloud cover will increase the change of fog dissipating
CNG: Firing an AA MG on the turret will no longer prevent the turret from then being rotated that turn
FIX: Player can no longer cancel waiting in place from the Unit Support Choice menu; menu now shown before message to player about waiting in place
FIX: A jammed or unjammed weapon will now be immediately displayed as such in the player unit info console
FIX: AI units were sometimes rotating a fixed turret to fire
FIX: If player hits a landmine or bogs down during overrun attempt, overrun is cancelled