Add commandline options

Can control the size of the rendered image and whether it is immediately saved to a file or displayed in a window, as well as the option to specify the filename

Possible future features:
        commandline options to toggle/control generation features
        commandline options to specify different shader files to use
        if the size is greater than the size of the screen, a panning feature or a scaling feature would be useful in order to see the full image before exporting it (currently a workaround on most linux window managers is to just resize the window to however large the actual generated image is and pan the window using the window manager)