Place assets in the PulseUnityAssets directory.

According to Section 3.1: Content organizationm of
https://unity3d.com/asset-store/sell-assets/submission-guidelines

- Access data files from StreamingAssets/PulseDataFiles, StreamingAssets
being a directory that will be directly copied in the file system of the
package, and is placed at the top level in the Assets directory:
https://docs.unity3d.com/Manual/StreamingAssets.html
- Add PulseEngineDriverEditor to ensure that pulse data files are properly
copied to the top level StreamingAssets folder in Assets, and that an
initial state file is set.