_gtkFontNew
_gtkFontNew creates a new Font object.
Prototype : fun [Chn S] ObjGtkFont
- Chn : the owner channel.
- S : a valid font description like "Arial 12 Bold". Can be nil, in this case, use the _getFont*Set functions to define its settings
- Return ObjGtkFont : the new Font object or nil if an error occurs.