Feature Request: Prompt user who exports the mesh for external tet removal

[zaracay]

I don't know how many people say something to the effect of, "All I see when I visualize a Cleaver mesh is a block."

Perhaps, when the user chooses to export the mesh, a prompt allows the to remove those external tets. The feature is already present in the Edit drop down menu, but new users seldom know to click that option.

This is a very low priority item, obviously, but could be useful for new users.