Author: Andrew Hancox
MDL-57457 mod_book: Implement tagging
http://git.moodle.org/gw?p=moodle.git;a=commit;h=01783146820a7efc33fc10b0de1ca920aa441c05
http://github.com/moodle/moodle/commit/01783146820a7efc33fc10b0de1ca920aa441c05
+ 3.3 en [removeallbooktags,mod_book]
+ 3.3 en [tagarea_book_chapters,mod_book]
+ 3.3 en [tagsdeleted,mod_book]
+ 3.3 en [tagtitle,mod_book]