Gui: Allow to unset modified state

[yorikvanhavre]

GuiDocuments have a "Modified" attribute that says if the doc has been modified or not (and prints an * in the titlebar). This attribute is read-only in the python interface (only getter is defined).

With NativeIFC, we are handling IFC files natively in FreeCAD, so all file loading/saving is done inside the module already, there is no more saving to .FCStd files. Last bit missing, not be annoyed by FreeCAD that the document has not been saved.

So this implements a resetModified() python method to unset the Modified flag.

I considered making the Modified attribute writable (implement a setter), but I'm not sure... People could play wrongly with that and they would loose the warning to save the file when closing FreeCAD. I thought maybe more interesting to implement a specific method, so people would be more aware of what they are doing and would be less prone to reset the modified state accidentally.

Not sure if that makes sense... What do you think @wwmayer ? @adrianinsaval ?

EDIT Following Werner's suggestion, this now sets the Modified attribute as read/write (previously read-only)

[wwmayer]

You can use Gui.getMainWindow().setWindowModified(False)

[yorikvanhavre]

oh excellent! this is unneeded then.
thanks Werner!

[yorikvanhavre]

Actually that does not solve the problem, using setWindowModified() does not really mark the document as saved, only the window title... so the MDI tab still has the asterisk, and the warning still appear when closing the document...

I'll reopen this issue for now

[wwmayer]

Shouldn't the method be called setModified() that accepts a boolean argument? This way it's consistent with the C++ API and also allows it to set the modified flag if needed.

[yorikvanhavre]

Yes you are right... That was my first question and I was hesitating in doing that, but indeed since it's generally done elsewhere in FreeCAD it seems safe to do it here. I'll refactor this PR