Observe a VR session from the same room using a HoloLens!
Open the HoloViveObserver directory using Unity 5.5.0f3 (64-bit).
To run on the Vive, simply hit the play button at the top of the Unity window.
Open the File -> Build Settings menu.
Make sure Windows Store is selected. If it isn't, select it and click Switch Platform.
Then click Build and select the existing App folder. This will export a Visual Studio project. Yes, you have to do this each time you make changes within Unity and want to deploy to HoloLens. If you just make code changes, you can skip the Build Settings step and build right from Visual Studio.
Within the App folder, open the Vive Observer.sln file. Do not be confused by the HoloViveObserver.sln file in the parent folder, that solution has no projects.
Once within Visual Studio, select Release and target x86, then choose whether you want to deploy to an actual HoloLens or the emulator.