New data source: company relationships from Thru.de

Thru.de has information on companies which officially pollute our
environment. The script downloads their SQLite3 database and extracts
company relationship information to thrude.csv. Two types of
relationships between companies are contained:
- Company 1 is owned by Company 2
- Company 1 is operated by Company 2

thrude.csv contains roughly 38K relationships.
Merge pull request #1 from marians/master

New data source: company relationships from Thru.de