* Added the builder script
* Removed the menu item
* Changed the brainToControl to public
* Added the scene for switching
* Modified according to the comments
* Removed the Builder and BuilderUtils script, made all of the logic into the Startup.cs
* Switched back to the previous way using PreExport method
* Added the return at the EOF.
* Resolved the codacy comments.
* Removed one empty line
* Resolved the 2 round comments
The Startup scene used for us to retrain and bundle example scenes
together already accepts the SCENE_NAME environment variable to choose
a scene. This change adds support for command-line selection of the
scene name so that `--env-args` can be used to choose the scene.
If both the environment variable and command-line flag are provided, the
scene will use the environment variable.