Small GUI stuff

- Colored virtual packages in the dependency graph
- Hide console window on Windows when running the GUI
- Fixed homepage & GitHub links not updating when GitHub info not present in the module
- Fixed a GUI exception when a suggested or recommended mod was not found during install
Oh! For what it's worth, `RelationshipResolver` will now only return modules which can be installed, and only throws an exception if a dependency can't be found. If it needs the user to make a choice, it throws a `TooManyModsProvideKraken`, which contains a list of options to choose from.

I don't know if you'd find that useful here, but you might. :)