Fixes, improvements and tweaks to various missions.

Localization update.

Added briefing videos.

Possibly fixed multiplayer.

Fixed the mod.
Makarov (Red Square mission) will now remain under AI control.

Fixed Pavlov's House mission.
Commissars in the Stalingrad (1st Soviet) mission will now shoot the player if he tries to retreat (so don't try to retreat, else you'll get killed - triggers only work for Alexei).
Smaller tweaks to other Soviet missions.
Graphical update for all loading and menu screens, minus the main menu background.

P.S.
I oofed the update, it broke the mod (kinda).

Reworked Pegasus Night mission (Pegasus Day will be added shortly).
Overall improvements to all missions so that they play more like the original.

Fixed a few US helmet localizations.

Fixed Pathfinder mission a tiny bit.
US soldiers have been taught how to buckle their helmets up. Only COs put up resistance and didn't want to hear about this.

Replaced Sd.Kfz 251/1 C to D in Pavlov's House mission.
Changed the Soviet plane in Oder River Country mission to be killable.
Changed rear MG on Sd.Kfz 251/1 D to the belt variant in Pathfinder mission.