UI improvements and a couple of fixes.

Fixes:
- deals with removeAssocDef issue in migration4
- simple fix for wikidata search-result order
- wikidata-url is set correct during processing of claims

Known issues:
- No backwards-compatibility to 0.0.1 (yet)
- Search entites are re-used acrosses wikidata-searches which introduces
  issues when items are searched and found across:
  a) different languages
     (currently there is just one language per item supported)
  b) different search-queries
     (currently there is just one ordinal-number per item & search-bucket supported)

Room for improvement:
- fix search order issue across various wikidata-searches
- process also all claimed number, string, globe-coordinate
  and commons-media values per search-result-entity (from wbgetclaims)
- extending model about sitelinks and languages
- implement a custom item page renderer
- complete the language selection-menu