OBJ_LOADER_DEMO: Modify the specular color for the materials with spec maps
OBJ_LOADER_DEMO: Modify the specular color for the materials with spec maps

The previous color was (0.0f, 0.0f, 0.0f), which didn't allow any specular. I changed it to
(0.5f, 0.5f, 0.5f), based on what "looked right". (1.0f, 1.0f, 1.0f) was too shiny for stone.

RichieSams/thehalflingproject,RichieSams/thehalflingproject,RichieSams/thehalflingproject