Add new argument to Application::newDocument() to create a temporary
document. Also exposed to Python API App.newDocument() with a named
argument 'temp'.
The temporary document is marked with status bit 'TempDoc'. The user
will not be prompt for saving when closing. The undo/redo is disabled.
The AutoSaver skips it. And the tree view will not show it.
PropertyXLink allows linking to/from object within a temporary document
without saving.
=============================================
New mechanism for on-demand signaling of undo/redo transaction finalisation.
The mechanism consists of:
1) A status bit that is set, when an object should receive this signaling (e.g. because changes during transaction have been inhibited)
2) The new function to be called by the Document undo/redo actions when the transaction is over (for those objects having the status bit set).
Note 1: The undo/redo signals are now outside the undoing FlagToggler, this means that:
1) a call to isPerformingTransaction will return false.
2) a recompute the slot of such a signal will not be inhibited.
Note 2: The undo/redo signals are called once the documentobjects that requested to be notified after the trasaction is over have been notified.
The consequence is that the viewprovider can rely on the documentobject having a correct status.
I think that the behaviour of Note and Note 2 is the wanted behaviour of this signals, I cannot rule out that other parts of FC rely on the old
implementation.
===========================================
fixes#4324
A multiline error message produces poor visualisation when used in the UI, while
there is no need for it to be multiline.
Remove runtime check when constructing FunctionExpression, in order to
support future built-in function. Exception will be thrown when
evaluating the expression to inform user about the error.
