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