Notification of string changes

Author: Petr Škoda
MDL-39088 migrate course format uninstallation to plugin_manager


http://git.moodle.org/gw?p=moodle.git;a=commit;h=8a953d629f6c9135fb4d1d94c341061f742700c4
http://github.com/moodle/moodle/commit/8a953d629f6c9135fb4d1d94c341061f742700c4

- 2.6 en [formatuninstallconfirm,core_admin]
- 2.6 en [formatuninstalled,core_admin]