SMW\UnusedPropertiesCollector

Continue to clean-up SMWSQLStore3SpecialPageHandlers in order to make
it parts testable while the SQL queries have not been altered.

SMW\UnusedPropertiesCollector
Code coverage: 100%
CRAP: 14

SMWUnusedPropertiesPage
Code coverage:
CRAP: 12

Change-Id: I90ca8384960221dbe52dce7b2c4a3e1f6cae88f0
Merge "SMW\UnusedPropertiesCollector"