xrMaterialSystem/GameMtlLib.h: Add Materials() function to allow rang…

…e-based for usage

xrRenderDX9/dx9HWCaps.cpp: properly load ATIMGPUD

XRay::ModuleHandle automatically adds ".dll" to the module name when
loading.

xrGame: Fixed crashes when loading some saves under Linux

xrRender_R2/r2.cpp: fixed invertion for position decompression params…

… on OpenGL

Update appveyor.yml