SVGHMI: Ensure that when widgets are nested in HMI:Switch widget, their sub-elements are taken as switch's choice in case their label match the syntax.

SVGHMI: Code cleanup for ToggleButton.

SVGHMI: Fixed last i18n changes meant to allow checking changes in PO files. Was making build exception when no PO files available.

IDE: Add a shortcut to project "Clean" action : F9

merge

SVGHMI: fixed embedded fonts family name not matching when using windows version of inkscape

SVGHMI: force svghmi build if any change in fonts or translation (.PO) files

SVGHMI: Add file type drag'n'drop to widget picker, for now drops widget's original SVG.

SVGHMI: silence debug output in generated xhtml.

SVGHMI: Implemented "Add Font" and "Remove Font", add font embedding in CSS at build time, tested ok with some OTF for now.

SVGHMI: Add font management buttons and icons, doing nothing for now

Fixed misuse of GridCellEditor in DurationCellEditor, potentially leading to crash on windows.

SVGHMI: Fix update of HMI tree in UI when loading from XML at start. Removed some dead code left after split of svghmi.py into svghmi.py+ui.py.

merge