Expanded "Global Default Layout" capabilities for project defaults.

Project default pages do not have the "Global Default Layout" and "Revert Page to Global Default" options.  Therefore, if a user accidentally changes the layout, it's not possible to quickly restore it based on the layout of the identical page on a different project.  If, for example, all Shots project default pages were capable of being controlled by a single global default, it would be easier to keep multiple projects in sync with each other (at least as far as page layout goes).