centering account nav tabs
user can publish if there's a publish plugin
first instantiate all plugins, then run all init()
removed plugin export-image from core

Instead, the plugin can be found here from now on:
https://bitbucket.org/jpp-cologne/plugin-export-image
changelog
updated duplicate link
removed auto-publishing
sorting chart actions, adding duplicate action
re-styled chart actions, removed publish-s3 ui
passing $app to api-hooks
Merge remote-tracking branch 'upstream/develop' into 2.0

Conflicts:
	controller/chart/publish.php
	lib/api/plugins.php
	plugins/export-image/package.json
	plugins/export-image/plugin.php
	src/Datawrapper/PluginManager.php