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* new warnigns when plugininfo are outdated or missing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
This patch includes:
* version column removed from modules table, now using standard config, this allows decimal version for modules
* version column removed from block table, now using standard config, this allows decimal version for blocks
* module version.php can safely use $plugins instead of module
* new plugin_manager bulk caching, this should help with MUC performance when logged in as admin
* all missing plugins are now in plugin overview (previously only blocks and modules)
* simplified code and improved coding style
* reworked plugin_manager unit tests - now using real plugins instead of mocks
* unit tests now fail if any plugin does not contain proper version.php file
* allow uninstall of deleted filters
