Implemented behavior:

* If no type filter is specified, we look up object types for the pkey provided
   * If there are hits other than person/role, we return those, and keep silent about any person/role hits
   * If there are no other hits than person/role, we output a message 'person/role history not available'

* If the user did specify object type filter
   * We try to find an object for each type with the specified pkey; if there is a match, we output either the history or the message 'person/role history not available'

Added Spec to cover for this behavior

Closes #213