Dialogue: disposition

Clicking a topic in the dialogue window can now return a response from the topic "Info refusal" when the NPC's disposition toward the player is not fulfilled.

If no response is found for "Info refusal", a fallback text is displayed. This text is the unicode character for ellipsis (yet present in existing MW dialogues).

Related bugs: [#497](https://bugs.openmw.org/issues/497), [#498](https://bugs.openmw.org/issues/498), [#500](https://bugs.openmw.org/issues/500)