Rename Query to PipSearchQueryValues

The Query class doesn't really represent a query, it represents a set a
values which can be used to create a query.

Issue #208.
query.php: Add skeleton class structure

Issue #208.
query.php: Implement StringQuery class

Issue #208.
query.php: Implement CompositeQuery class

Issue #208.
log: Use more geneic class layout and add usage

Issue #208.