preliminary Bulgarian support.

Stolen from
https://github.com/fzaninotto/Faker/tree/master/src/Faker/Provider/bg_BG
Improved names in Dutch
Apply Dutch naming convention for married partners
Implemented ssn for nl_NL using BSN
Merge pull request #115 from mdxs/improve_nl

Improve names in nl_NL provider
Merge pull request #116 from mdxs/ssn_for_nl_NL

Implemented ssn for nl_NL using BSN
Merge pull request #114 from bretjb/bulgarian

preliminary Bulgarian support.
Fixed typo in change log
Merge pull request #117 from mdxs/patch-1

Fixed typo in change log