Simdify Runtime

Modified the runtime to allow you to specify files in two ways: you can specify a file directly as a command line argument using the .spa_binary_graph extension to load a single file, or using the .txt extension to specify a set of files.

Modified the runtime to allow you to specify -autoquit, which causes the runtime to exit after a paint operation has completed. Otherwise the runtime continues to execute until you stop it. Note that this functionality is only supported on Windows at present.

Modified the runtime to allow you to specify -hidewindow, which causes the runtime execute and render without showing a window. Note that this functionality is only supported on Windows at present.