How can I merge two MonoDevelop projects together again manually?

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http://askubuntu.com – My group partner and I are creating a MySQL database application with a GTK# frontend. Our application consists of a main window with information displayed in multiple tabs. My partner started most of the implementation, then he gave me a copy of the project folder so I could implement half of the tabs and he could do the other half. Now we want to merge our work back together, but we weren't using source control (yeah, yeah, I know...) and we aren't sure how to easily smush them back together by hand. Any suggestions? (HowTos)