Retirement of the Base.cfg file that is used for none MESH textures

[daves-ssu]

I propose that for OpenOrbiter, that the Base.cfg file is retired. This file dates way back to one of the most earliest builds of Orbiter and is used to load textures used by the various base elements such as HANGAR and TANK. I propose that it be replaced with direct loading of the textures like they are for MESHes that define OWNMATERIAL. This will eliminate one potentially troublesome conflict point when installing add-ons that rely on Base.cfg editing.