Add missing title block variables to 'folio properties' window

[LambertusIJsselstein]

A folio has some default title block properties that can be used in a title block like 'Title' and 'Author', this is great. However, a lot of title blocks will also use one or more custom fields and, every time the user adds a title block to a folio, the user has to create the variables in the 'Custom' tab of the 'Title block information' section of the folio property window.

It would be great if the missing/undefined title block variables are automatically added to the 'Custom' tab, or simply appended the existing 'Main' title block properties.

For example:
Create a new folio and add the ISO7200_A4_V1 title block to the folio. You will see a number of variable placeholders in the title block like %{department} and %{owner} etc. These undefined variables should automatically be added to the Folio properties window so the user only has to fill in the missing values instead of adding the variables and values.

[titanic-jb]

I'd would like to add the handling of revisions.

Take the same folio template. It contains variables %{rev}, %{status} and %{approval}.

Revision number handling is an important thing. To keep it simple, one could only allow one revision number, which applies to all folios, instead of having single folios, which do have different revision numbers than the rest of the document.

If the strategy is, to allow only one revision number for the whole document, it would be very convenient, to have a "Change Revision" Menu, which opens a PopUp dialog, prefilled with the name of the actual user, date and time, asking for the actual revision number to be appoved.

It would be very nice, if the history would also be presented in a tabular form.