v0.1 release

Finally, the first release version of WACVR is there!
It's still not perfect but it's pretty useable now!
You can now make a custom environment just like skybox! Just make a prefab then attach the PrefabLightData script to the prefab root. Bake the light map with Assets/BakePrefabLightmaps, set the prefab as Assetbundle then export it! Be careful, you need to rename the asset bundle to *.abf and then put it into StreamingAssets/Environment folder.