As a developer, I want a command-line interface for creating VWF apps

Create a new VWF application with:

    $ vwf create my-app

Should create an app with only app-specific files in the folder. Framework files should remain stored elsewhere.

**IDEA:** Add -v / --version flag for checking the version.

Redmine [#2962](http://redmine.virtualworldframework.com/issues/2962)

Closes #2962