include server time (as timestamp) in visitor actions (visitor live API)

unset a possible set idSite in the logout url, this should fix the error message not having access for idSite after logout.

removed the tests from Ecommerce plugin otherwise we have the screenshots in this plugin (in core) etc

Better goals management

Splitted referrers overview into "Overview" and "All Referrers"

moving "Plugins" and "Themes" to manage section. Displaying Marketplace only to superusers as it is already displayed in the user menu anyway

Fixes #6930, allow plugins to test against minimum required Piwik version in travis build. Includes deprecation to testing against 'latest_stable'.

Disable gc collection for PHP 5.3.3 to avoid segfaults in Travis https://bugs.php.net/bug.php?id=53976