how is this working?  `read[]` is supposed to use the sbt.boot.properties to read something, so how can you use it to define sbt.boot.properties?

I think this line can just be:

```scala
properties: ${activator.boot.properties-${user.home}/.activator/version-${activator.launcher.generation-%d}.properties}
```

and you'll be ok.  Otherwise, I have no idea what was happening before....