first pass at implementing the windows version of the new interface methods
IViewPort now has a public method to call whenever you want to notify it that its underlying file has been changed.
Added 3 tests showing how the Editor and ViewPort should behave with this new functionality.
- Editor should hook up ViewPorts whenever a new tab is opened
- Editor should clear out ViewPorts whenever a tab is closed
- ViewPort should reload when the file is changed and it is not.
Note that the model isn't implemented yet. This is just some failing tests.