Moved logging functions to dbg.h (tier0) and export them from the dll.
Added additional functions for checking bad pointers (debug only!).
Reduced output code size.
This crash happens when the BSP is missing a lot of shaders and materials.
The call originates from 'R_DrawWorldMeshesDepthOnly()', but it is unclear which missing shader is causing the nullptr. checking for a nullptr here should be sufficient to deal with this kind of missing shader
