counter: 1.3.1 - Refined/Simplified the type-mapping

* Removed all explicit type-mappings for the internally used types.
* This greatly simplifies the configuration, because it is sufficient to
  configure the trusted package to serialize/deserialize all internally
  used types.
* To make this possible, the type-mappings for the outgoing messages are
  specified with `Produced.with()` in the ``to()``-operation.