Refs #9077 Modified checks, File-> Close and Coadd

The following has been fixed:
* File->Close Refl Gui now actually closes it, as until now it had loaded help.
* Clearing, reloading or opening a table will now do a modifed check and offer to save
* Clearing the table no longer sets the mdoified flag
* Coadding workspaces now works as intended
Refs #9077 Refactored save check code

Some of the save check code has now been refeactored into a separate method. One check messages couldn't be refactored as it's asking a different question.