Bug 1597 - Enh: Greater clarity over status of versions needed

- For ALPHA builds we do a check version with the Welcome screen (if welcome screen is enabled).
- A 'Check Online' in the About box provides a new route to check version
- Check Version now passes CommitId and Build Date/Time to identify a version.

To actually close the bug we need the javascript on the server page to put up informative messages.

src/Menus.h

@@ -417,6 +417,7 @@ void OnAbout();
 void OnQuickHelp();
 void OnManual();
 void OnCheckForUpdates();
+void MayCheckForUpdates();
 void OnShowLog();
 void OnHelpWelcome();
 void OnBenchmark();