Added interface IConsole to GoodGet, to abstract away the user interface.
Added StandardConsole class, implementing IConsole by writing content to the standard console streams (stdout, stderr).
Made the IConsole implementation be injectable into the GoodGet module by means of the GoodGetModule.Injections class and a new Console property.
Injected StandardConsole as the IConsole implementation when doing Install using a new PackagesFolder instance.
Changed all use of Console.Write[x] to use the injected IConsole instead.