Potential issue with the loading mission GUI

This is more of an oversight I guess than a real bug since it can be easily resolved/worked-around.

The problem lies in that the loading gui doesn't have a Back or Cancel button like the TGE/TGEa version had. Let's say that you have a mission that fails to launch for some reason; for example: a syntax error in the player datablock.... so you're stuck with the loading progress bar and text that says "LOADING OBJECTS" -- what do you do?

- Alt F4 ?
- Ctrl Alt Del & then Task Manager ?
If you're on Windows, but why be forced to use the brute force approach?

- Toggle GUI Editor -> File -> Quit
- Toggle GUI Editor -> Switch to the MainMenuGui -> toggle GUI Editor
- Toggle the Console -> loadMainMenu();

While I would hate to clutter up the spiffy new loading screen with a button, perhaps it needs one for just this very reason.