textray demo for unity
Summary:
Previously I need to back out D32220626 and then apply D31841609 to run the textray unity demo. It's hard to have other people to take a look how this textray demo looks like.
I copied the textray demo (a single file) from pytext folder to unity folder and applied the changes needed. This way, other people can also run this textray demo. This also makes my dev environment cleaner.
Test Plan: buck run mode/opt :textray_demo
Reviewed By: mleshen
Differential Revision: D32537190
fbshipit-source-id: 5df6347c4bec583c225aea9f98fbc9f37b5d3153
