Include "Editor Default Resources"

[rev087]

Editor Default Resources is a special directory in Unity that allow UI scripts to retrieve and use assets. The problem is that it is required to be located at the root of the project, thus it is not currently included in this repository.

For packaged releases, it's a simple matter to include that folder in the package. For contributors in the other hand, currently it's required that they export the icon PNG files from the /Editor/Art/Hivemind.sketch Sketch file.

A possible solution would be to include a build script that uses the Sketch Tool to automatically export the icons.

[rev087]

For now I just included the generated files in /Editor/Art/Hivemind/. Ideally a build step should copy them over to /Editor Default Resources/, or use the method above.

For now, users can simply copy the /Editor/Art/Hivemind/ directory to /Editor Default Resources/Hivemind/.