added a test for expanded and flat. Please not that the expected flat result is wrong, it might work when merging the flattened refactoring

Making algorithm processing unique visitors across websites actually work, refs https://github.com/PiwikPRO/plugin-MetaSites/issues/3

* No longer any segmentValue in subtables, this was a bug
* Referer.getReferrerType should not have any segments
* Order of some segments slightly changed in metadata output since we
  do process them earlier now
* Append segemnt refererType=search to keywords

refs #4633 rename segment filter to segment, fixed a bug re visitTime and extracted code into a filter

Add new --w3c-field-regex option to log importer which allows specifying regex for any w3c extended log field. Can combine this option w/ --regex-group-to-...-cvar options to track any field that the importer doesn't natively recognize.

Replace --api-to-cvar params with --regex-group-to-cvar options in log importer for greater flexibility. Added an --ignore-groups parameter to allow ignoring certain parsed groups (like userid). Also added available regex groups to log-format-regex documentation (not added in generic way unfortunately).

refs #6705 fix integration tests that have changed as a user metric is no longer returned in those examples

Add option to map API tracking parameter to custom variable in log importer script. Includes change to ImportLogs system test and fix for import log custom variable handling (old behavior was to not set multiple custom variables if they were set already instead of simply adding custom variables).

Fixes #6436, fix concurrency issue regarding duplicate actions by always using least idaction and deleting duplicates when they are found to be inserted. Since tracker process can potentially fail before duplicates are removed, added test to make sure reports work when duplicate actions exist in the DB.

Fixing build failure, 4 distinct metrics no longer appear due to bug fix (distinct referrers are 0, so no metric added).