allow uppercase in generated textures specification

Texture.cpp

@@ -1292,6 +1292,7 @@ texture_manager::create( std::string Filename, bool const Loadnow, GLint Formath
         erase_extension( Filename );
         // clean up slashes
         erase_leading_slashes( Filename );
+        Filename = ToLower( Filename );
         // temporary code for legacy assets -- textures with names beginning with # are to be sharpened
         if( ( starts_with( Filename, "#" ) )
          || ( contains( Filename, "/#" ) ) ) {