Author: Helen Foster
MDL-24405 reverting lang strings thanks to Chris Collman for review
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ca6dd3edc54d6d4dd68e220e7309250ad8a1b123
http://github.com/moodle/moodle/commit/ca6dd3edc54d6d4dd68e220e7309250ad8a1b123
+ 2.0 en [addanendofbranch,mod_lesson]
+ 2.0 en [addedanendofbranch,mod_lesson]
+ 2.0 en [cannotfindpagerecord,mod_lesson]
+ 2.0 en [endofbranch,mod_lesson]