Updated the VSIX to make it Visual Studio 2019 compatible

[patware]

Many firsts for me:

• First "real" use of git
• First time git contribution (fork+pull request)
• First Visual Studio Extension

A good code review will be necessary, lol.

I took the liberty of changing the template of the generated WPF451 project type, to reflect new changes in the CommonServiceLocator namespace, and small changes to make the generated code compile without warning/error.

[simonbuehler]

any reason why this isn't geting merged? its nearly a year now!