Performance tweaks for search

[lonvia]

This adds various minor performance tweaks for search:

• running tests against a complete set of combinations of various search parameters revealed some more queries where the Postgres query planner uses the wrong index
• give even more preference to the index over names to the one over address parts
• add penalties for one-letter words (which cause trouble with abbreviations like 'U.S.A')

as well as timestamping for debug output in text (helps with finding the long-running SQL).