Playing with NSImageView and NSImage

- Created a new window to display a beautiful image of an office in New
York
- Removed an extra property which has somehow made its’ way into
‘AppDelegate.h’ (I’m talking about ‘make’)
- Created a property in ‘AppDelegate.h’ for the NSImageCell containing
the New York office image (I was just playing around when I made it but
I’m leaving it here because it may come in handy when I try using
NSPasteboard to copy it to the clipboard.)
- Created a new NSMenuItem to call the action
‘displayOfficeNewYorkWindow’ which will display the window with the
image. It will also hide the window if clicked when the window is
visible.