Refs #4059 Converting dozens of plugins/* classes to use Namespaces, \Piwik\Plugins\*
Added namespaces to functions.php files in the five plugins that had one
Work in progress
Merge remote-tracking branch 'origin/master' into plugin_namespaces

Conflicts:
	core/Tracker/Request.php
	core/ViewDataTable.php
	core/ViewDataTable/HtmlTable/Goals.php
	plugins/Actions/Actions.php
	plugins/Annotations/API.php
	plugins/CoreHome/CoreHome.php
	plugins/DBStats/DBStats.php
	plugins/DevicesDetection/DevicesDetection.php
	plugins/Goals/Goals.php
	plugins/Live/Live.php
	plugins/Referers/Referers.php
	plugins/UserSettings/UserSettings.php
	plugins/UsersManager/API.php
	plugins/VisitTime/VisitTime.php
	plugins/VisitorInterest/VisitorInterest.php
Merge with Master + fix build + Namespaces conquest check
Refs #3942 Now themes don't need to have a PHP file, themes can simply specify a "stylesheet" entry in the plugin.piwik.json, this CSS/less file will be loaded as if it was registered with the  css event
Merge branch 'plugin_namespaces'

Conflicts:
	plugins/UserCountryMap/Controller.php
Merge branch 'master' of github.com:piwik/piwik into pleineLune__theme-details
Theme default data table link color for PleineLune
Add space between site selector and main menu on tiny screen
Make the dashboard menu smaller on tiny screens
Adapt the size of the segment selector on tiny screens
Activate the responsivness of the dashboard with the meta viewport