Refactor and clean-up

[pilif0]

While I am going through the code, I will do my best to clean it up and make it more readable. This includes adding documentation and comments where useful, renaming variables to reflect content, replacing tabs with spaces, indenting, ...

[PetrosPapapa]

Hey @pilif0, I think using scalafmt to fix my horrible and inconsistent style would be much more productive and effective in the long term. The default configuration is supposed to be very good, but happy for you to suggest custom options.

[pilif0]

@PetrosPapapa It would in the long term. I did this by hand, as I had to read the code to understand it anyway. I can add the configuration for that tool as part of this PR, so that it is available for use in the future.

[pilif0]

I tried to configure scalafmt as best as I could. One issue I still have with the current configuration is with how it multilines long argument lists. For example:

  def this(store: PiInstanceStore[Int], l: PiProcess*)
          (implicit system: ActorSystem, context: ExecutionContext, timeout: FiniteDuration) =
    this(store,SimpleProcessStore(l :_*))

is formatted as

  def this(
      store: PiInstanceStore[Int],
      l: PiProcess*
  )(implicit system: ActorSystem, context: ExecutionContext, timeout: FiniteDuration) =
    this(store, SimpleProcessStore(l: _*))

which, in my opinion, is not an improvement. However, I don't know if there is a configuration option for this case, so we might have to live with this.