Add ability to import the setting of def_document_tabs_orientation

[rowbearto]

I prefer to have my file tabs in the bottom, and not the top.

As indicated in this thread: https://community.slickedit.com/index.php/topic,9287.0.html

It is possible to do this by setting  def_document_tabs_orientation to 1.

Recently, I did an export of my config on one machine and imported it into another machine. This setting was not carried along.

So my request is to be able to export/import this setting.