Suppress redundant topics in detail panel (#315).

Redundant topics are suppressed in the detail panel's related topics listing. A topic is regarded redundant if 1) it is already represented in the detail panel's upper area (the "model-driven box structure"), and 2) there is a "Composition Definition" in the underlying model.

Core API:

The Association interface has a new method:
{{{
boolean isPlayer(TopicRoleModel roleModel)
}}}

The REST Client has 2 new methods:

{{{
dm4c.restc.get_related_topics(topic_id, sort)
dm4c.restc.sort_topics(topics)
}}}

See #315.