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 #6919, do not check for host in regex group in log importer if format has no regex. Also add nginx json log to log importer system test.

Adding support for parsing amazon cloudfront log files in log importer & making W3cExtendedFormat treat time-taken field as seconds by default (since that is what the W3C format specifies). Also add support for event tracking and cloudfront RTMP logs (which provide event logs). Also allow multiple spaces in between W3C extended log files. Allow derived classes of W3cExtendedFormat to define new custom field regexes.

Refs #5980, parse cs-username variable in IIS logs and use as userid when present and not anonymous. Includes changes to ImportLogsTest.

Refs #6795, add --iis-map-field option to allow users of log importer script to parse log files created using the IIS Advanced Logging module. Includes tests for such a case (including python unit test + PHP System test).

refs #5940 put tests in correct folders, better testsuite names, some tests still fail and I cannot figure out why

User ID is NULLable now results in expected tests results: nb_users = 0 when no user id was set. refs #3490 #6162

Refs #3632 New test case: replaying logs and forcing a window look back (forceLargeWindowLookBackForVisitor=1)
=> The visitor is now marked as "returning" as expected

Refs #3632 Creating a test case: same visitor (same IP + idvisitor) visits the website on two different days.
Visitors on second day is marked as "new" because window_look_back_for_visitor is not set.

Forcing all recorders and recorders max payload to 1, to prevent random behavior (eg. in Live.getLastVisitsDetails, the pageIdAction may be random order if recorders import data in random thread order)

Fixes #4628 --enable-bots now works as expected + our importLogs integration test shows that this wasn't working before.

 * making some tests pass == fixing bugs