Change throws semantic

* Wickject, now in v0.3.0, will throw when any field is found,
  that is annotated but not provided for by the injector.

  The general idea here is of course to encourage well-defined
  tests, where all injected fields are explicitly cared for. This
  should result in a more fail-fast type of setup in tests - which
  I believe is good.

  Please prove me wrong, and we might do something like a lenient
  flag.