example datasets

[SchmidtPaul]

Add more example datasets with these features:

• is large enough that find_potential_dups() has to go trough if (NumberOfComp > maxNumberOfComp).
• has different languages for detect_language()
• has different country names in abstract, title, keyword for detect_country()
• has nice entries for showing the smart handling of Online Address via handle_obvious_dups()