IOS: Call exit(0) when exiting to prevent hanging

Prevents the process from hanging on exit when using the
Quit button in launcher or a game's quit function

backends/platform/ios7/ios7_osys_main.cpp

@@ -414,4 +414,7 @@ void iOS7_main(int argc, char **argv) {
 		//*stderr = NULL;
 		fclose(newfp);
 	}
+
+	// prevents hanging on exit
+	exit(0);
 }