* Application menu : added 'Import' section.
* Loader: 
 - added access to the different type of Importer.
 - added method to open image with a specific Importer.
* Open image dialog:
 - now use display file filter from Sequence importer.
 - importer selection done from selected file filter.
* MainInterface:
 - added .isHeadLess() method.
 - added .getCommandLineArgs() and .getCommandLinePluginArgs() methods.
Prelemenary support of importer action.