update issue #136 : Application can now open multiple windows for editing new graphs in the same process 
Uses same techniques as project wizard generated MFC projects for multiple top-level document windows
MRU_list class now easier to maintain for future menu changes
Added File/New Window and File/Close Window menu items.
First open window is the main window - application will always close if this window is closed

git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@221 c2f33eb2-41b2-391d-4cb4-d9d0608729ba