When running tests and tests fail with a NOTICE/warning, show the backtrace in the response.
Factoring out archiving Custom variables + cleaning it up (breaking down huge archiveDay function into several methods)

Renaming some core code to make sense (sumMetrics and makeEmptyRow instead of ugly names)

TODO: continue with other plugins
Adding setting for limiting Custom Variables report in the config file, separate from the referrer config.
This is especially useful to fix an ecommerce bug where "Visits" don't display properly for all products, since we used to truncate after 50 rows.
Also sets by default to 1000 to ensure ecommerce tracking mostly work.
Refs #3569
Factoring out + cleanup Archiving DevicesDetection
Factoring out + cleanup Archiving Goals
Factoring out + cleanup Provider, UserCountry, Goals
Full refactor of UserSettings plugin, now it's starting to look good
    // OMG THIS IS SO WRONG!
    // use segment instead
VisitorInterest factor out
Minor
Introducing new PluginsArchiver class. Plugins can create an Archiver inheriting this abstract class.
factoring out the shouldArchive logic
fix
missed these earlier, factoring out
Merge branch 'master' into events_refactor

Conflicts:
	plugins/Actions/Actions.php
	plugins/CustomVariables/CustomVariables.php
	plugins/DevicesDetection/DevicesDetection.php
	plugins/Goals/Goals.php
	plugins/Provider/Provider.php
	plugins/Referers/Referers.php
	plugins/UserCountry/UserCountry.php
	plugins/UserSettings/UserSettings.php
	plugins/VisitFrequency/VisitFrequency.php
	plugins/VisitTime/VisitTime.php
	plugins/VisitorInterest/VisitorInterest.php