Improved project and item templates

[JaiganeshKumaran]

See #814

• Removed unnecessary content that are basically throw away
• Removed unnecessary spaces
• ViewModel now implements INotifyPropertyChanged (At least that's useful than having a Int32 property)

[sylveon]

If you are making the view model template implement INotifyPropertyChanged, then I would suggest making another template which adds a basic runtime class because I currently use the view model template for that, for lack of better option.

[kennykerr]

Unfortunately, we have nobody on staff to maintain or test the project templates so they are largely frozen except for critical fixes. Everything under nuget/vsix/natvis is unfortunately very brittle and requires manual testing. Feel free to fork them and provide superior project templates but these will have to stay as they are.