* added column to the ROI table.
* some fixes in the new ROI panel.
* minors change on layers table.
* some refactoring.
* Rois panel:
 - layout modified again, should not change much now !
 - table support now much more columns (selectable).
 - XLS export always take all columns in account.
 - others improvements you will notice.
* Layers panel:
 - we can now edit the layer's name directly in the table.
 - accept delete command through the table.
 - some others minors tweaks.
* added ActionManager class which  allow to access command action
in a centralized way (will be improved in future).
* added GeneralPreferences.getResultFolder() / setResultFolder() methods
to get/set the default application "results" folder.
* more internals commands accessible through the search bar.
* replaced XLSManager by XLSUtil so use the later one now.
* improved ColorChooserButton rendering.
* IcyButton: fixed minors issues.
* some improvements in the Exception Handler engine.
* some bugfixes.
* some refactoring.
refactoring