Create leidraad.csl

This is the first release-candidate for the dutch legal reference style 'Leidraad voor juridische auteurs' or 'Leidraad'.
Update leidraad.csl

Release-Candidate 2. Comments by Adam Smith reviewed, changed things, improved it.
Update leidraad.csl

Fixed: note/in-text (wrongfully changed) and quotes
Update leidraad.csl

V.1 RC4:
- Removed text-case="sentence" to respect user-input
Update and rename leidraad.csl to leidraad-voor-juridische auteurs.csl

Ready to be published (merged)
Update leidraad-voor-juridische auteurs.csl

(forgot to change the id... / fixed)
Rename leidraad-voor-juridische auteurs.csl to leidraad-voor-juridische-auteurs.csl

Some weird mistake with file-name fixed.
Merge pull request #753 from JoelHendriks/patch-1

Create leidraad.csl