Implement INotifyPropertyChanged on ModListItem

[Meivyn]

This should solve #380 without the issues mentioned in #398, on top of that it will also make the view being refreshed in real-time as you select, install, or uninstall mods. It also fixes the selection behavior of the checkboxes to be more appropriate in my opinion, but you may want to double-check it is for you.

I still have to figure out how to refresh the view when you uninstall all mods from the options, but that isn't a side effect of this PR and happens regardless.