Solves a lot of issue of user not realising values are case sensitive.
Mainly solves issues with FNA3D_FORCE_DRIVER and /gldevice:%s launch argument, aswell as FNA3D_OPENGL_WINDOW_DEPTHSTENCILFORMAT.
Changes SDL_strcmp to SDL_strcasecmp in FNA3D_PrepareWindowAttributes() and OPENGL_PrepareWindowAttributes()
Solves a lot of issue of user not realising values are case sensitive. Mainly solves issues with FNA3D_FORCE_DRIVER and /gldevice:%s launch argument, aswell as FNA3D_OPENGL_WINDOW_DEPTHSTENCILFORMAT. Changes SDL_strcmp to SDL_strcasecmp in FNA3D_PrepareWindowAttributes() and OPENGL_PrepareWindowAttributes()