Include the assets in the C++ tutorial AppVeyor artifact

[prock]

Just downloaded the AppVeyor artifact however it didn't include the assets to be able to run the Tutorial.

[Jens A. Koch]

Good point.

Ok, to resolve the assets paths, i need to adjust the folder structure of the artifact, too:
Because the assets are expected two folders up: defaultFontPath("../../assets/fonts/FreeSans.ttf");.

\tutorials
   \- tutorial1
\assets
  \- fonts
  \- etc

[Jens A. Koch]

Here we go:
https://ci.appveyor.com/api/buildjobs/7vyi0s489vsaxv6o/artifacts/tutorials-dev-c8d7209-VC14.zip