Update help message in case tracker fails.
Move code used only in production to its own module.

Production-only code is what needs to be loaded only when XMPPVOX is run as a PyInstaller bundle.

It adds the dependency on win32api, available only on Windows.
XMPPVOX is still multiplatform in development mode.
Comestic changes.
Fix bug cannot create diretory when file does not exist but directory does.
Rename _ping -> ping_once
Remove global MACHINE_ID.

This when we can control when to read the MACHINE_ID, and end up with more pure functions in the tracker module.
Move general error handling one level up.

Now, after configuration is done, everything goes into a try...except...finally block.
Prevent console window from closing when an error happens.

On Windows, we would be unable to see what was the error if the window simply closed.
Generalize 'read_dosvox_menu_items' with 'read_dosvox_ini_items'.
Clean up exception handling again!
Track XMPPVOX installation.

Closes #17.