Overview

This is a follow up task for adding documentation to MRTK Event Propagation feature branch.

Currently several files have inconsistent copyright headers. Replace with:

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See LICENSE in the project root for license information.

Is your feature request related to a problem? Please describe.
Currently MapRenderer.Raycast api will raycast to everything on the map. It would be helpful to add a method that has reference modes similar to MapPin.AltitudeReference. For example being able to sketch only on the terrain while ignoring buildings. Or when dragging 3D models onto the map, ability to cast only onto the terrain...

Port some of the initial HTK focus tests to ensure focusing works properly

processId is now a uint, this helper method should be updated.

we should also look for related places that were missed in the change from int -> uint

I like .ply, it's an easy format that supports vertex colors! .ply files are often used for point clouds, so it could be good to consider point cloud rendering when importing .ply files as well.

Might be able to find a nice library for this on here:
https://github.com/nothings/single_file_libs

CPU timestamps may not always paint an accurate picture of missed frames in Unity. To gain a more accurate representation of missed presentations we should integrate this API for UWP apps.

As a documentation suggestion -

I found that I needed to use Unity version 5.6.1f1 and Visual Studio 2015 -- Update 3.

For the Unity "Build Settings" -- I adopted the following changes to the ReadMe's screen image of Build Settings:

Target Device -- HoloLens
UWP SDK -- 10.0.14393.0

![image](https://user-images.githubusercontent.com/1923683/37540614-0145e45c-292e-11e8-90

Currently, sessions are stored in the application memory. Adding a memcached driver will let developers share sessions across app instances