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

Notes:
  - Modified ManySitesImportedLogs fixture to add segments if desired.
  - Switch to synchronous execution of curl requests until deadlocking issue in archive processing is dealt with.
  - Fixed bug in LogAggregator where if a segment required a subquery, archiving would failed.

Refactored archive data querying code. Removed tree-like data structure from Piwik_Archive, added memory optimizations for archiving (not storing archive processing instances), added optimization for querying data indexed by site + date, added ability to select multiple blobs/metrics at once (from different plugins), added optimization to Piwik_ArchiveProcessing_Period where numerics/records are selected all at once instead of one at a time.

Also added data access layer object for archive querying code, allowed anonymous function objects to be used as DataTable filters, and removed 'timestamp' DataTable metadata.

git-svn-id: http://dev.piwik.org/svn/trunk@7269 59fd770c-687e-43c8-a1e3-f5a4ff64c105

 * Ensuring column names stay in same order when idsites=all 
 * adding empty columns when they are not set

git-svn-id: http://dev.piwik.org/svn/trunk@5519 59fd770c-687e-43c8-a1e3-f5a4ff64c105

VisitsSummary API does NOT call Actions API now.

git-svn-id: http://dev.piwik.org/svn/trunk@5400 59fd770c-687e-43c8-a1e3-f5a4ff64c105

refs #1454 new action metrics are only accessed by actions plugin, bounce rate fix, changed color of second line chart series, updated expected test files

git-svn-id: http://dev.piwik.org/svn/trunk@5393 59fd770c-687e-43c8-a1e3-f5a4ff64c105

git-svn-id: http://dev.piwik.org/svn/trunk@5392 59fd770c-687e-43c8-a1e3-f5a4ff64c105

 * API functions returning data now have a new optional 'segment' parameter. segment can define a Visitor segment dynamically that will be applied to the report. For example, &segment=country==FR;actions>=3 (AND, OR supported. Only == and != supported currently, but easy to add more)
 * For API requests with a segment parameter, the reports will now be processed on the fly, and only the requested plugin report will be archived.
 * All plugins now define the 'segments', with a name, category, SQL field, filter, etc.
 * Simplifying archiving code a bit
 * Fixes #2069 Exit rate computation
 * New widget: lists the Top Keywords for a page URL, Widgets for a website only. Maybe later we could create a widget category "For your site"?
  * This widget is pretty cool SEO wise, but maybe the PHP snippet should do caching (not so good hitting the API on each page view... but why not?)
 * still to do!

git-svn-id: http://dev.piwik.org/svn/trunk@3870 59fd770c-687e-43c8-a1e3-f5a4ff64c105