[API] Some commands breaks command line batch execution

There are some API calls that breaks Harmony command line batch execution because it launchs “confirmation” dialogs when executing like:

column.removeSoundColumn(name);

When trying to execute those API calls in batch mode, it fails with this error:

QWidget: Cannot create a QWidget when no GUI is being used

It would be great to check in all API implementation when we are in batch / non GUI mode to avoid creating QTWidgets

Also, it would be great to have a API call like about.isGUIMode() or something like that. Currently about.isInteractiveApp() returns true always, or at least it returns true when we launch Harmony with -scene -batch -compile arguments.