Fixed erroneous shortening: only shortening articles, and only if they’re not inside a ‘bijlage’
Merge branch 'master' of https://github.com/CENMetaLex/metalex-converter

* 'master' of https://github.com/CENMetaLex/metalex-converter:
  Added script for generating PROV statements from repealed regulations
  Added handling of organisations
  Only linking agent and organisation to root expression_uri, not the ‘functie’ element and its children.
  Now generating PROV for every element.
  Safer handling of attributes