Changed platform image load and Clean up

-Platform images not load based on a string passed in main
-removed functions and variables no longer needed. These include:
--type variable, Return function, and the type return in the read
funcion.
--Global variables SDL_Surface plat1, plat2, etc no longer needed, so
also removed.
-provided a clean_up function in platform object to free surfaces and a
loop in the main clean up function to run through all of the platforms
in the vector.
-Next step is to prepare for a git merge to main.