Viggen - PBR Speculars (Roughmet) 1.1

New speculars to support dieletric/metallic materials with Deferred Shading ON
Mainly done for use with my add-on skins.

1.1
-Removed default 37 livery description.lua (DCS 2.5 automatically load roughmet definitions if found)

-Added roughmet for SB-71 weapon