Multiple issues fixed:
* Fixed order of the statements to avoid access to undefined variables.
* Fixed population of the SQL query parameter to make sure they match
the placeholder in the query.
* Fixed missing table aliases in the second query to make sure the query
actually works as expected.
Added new functions to editor api - set/get_text so the
original form text can be determined from an editor.
When calling use_editor() you should first call set_text() with
the text that will be inserted in the form element.
There is also a new scheduled task for cleaning Atto autosave drafts.
Includes:
* update checker refactored to \core\update\ namespace
* plugininfo classes refactored to \core\plugininfo\ namespace
* plugin_manager renamed to core_plugin_manager
* redirect back to original page after plugin uninstall
* fixed assign subplugin uninstall
* move assign subplugins under the assignment in admin tree
* fixed plugininfo for all question related plugin types
* auth uninstall support
* added missing block dependencies
* added theme uninstall
* subplugin types are following the plugin on plugin overview page
* several performance improvements in plugin manager
* new warnigns when plugininfo are outdated or missing
* multiple fixes and other improvements
