Replaces the standard Drupal edit screen for nodes with an enhanced drag-and-drop editor.

If upgrading from 2.0.x:

• make note of applicable settins under "admin > Settings > Content Authoring > Mercury Editor settings"
• disable all Mercury Editor submodules (see drush command below)
• upgrade to 2.1.x with composer
• clear cache, and manually restore applicable settings

drush pmu mercury_editor_components mercury_editor_layouts mercury_editor_content_moderation mercury_editor_scaffold mercury_editor_dialog mercury_editor_skip_form mercury_editor_edit_tray mercury_editor_style_options mercury_editor_iframe mercury_editor_tabs mercury_editor_inline_editor