Added the commodity merchant for machinists.

Hotfix.

Machinists trade caravans now prefer to use bison as their pack animal instead of the humble muffalo preferred by the outlanders.
The stock generation of machinists war merchants have been reworked, they will now generate a good stock of industrial - and only industrial - weapons and armor.
The academic trader will now sell a wider variety of stuff.

Updated the Combat Extended patch for the merchant pawn type.

Added a merchant pawn type to machinist traders.

Hotfix.

Added a field medic pawntype. These pawns are capped at 2 per raid and always carry medicine of some sort.

For Combat Extended users, reworked the way shields are assigned to pawns.

For Combat Extended users, some elite units may now come with shields.

For Combat Extended users, some pawns can now be found spawning with spare grenades.