Author: Petr Škoda
MDL-34674 use browser built-in spell checking in all browsers except < IE10
http://git.moodle.org/gw?p=moodle.git;a=commit;h=0ac97084faa3d0114b8cb6d69332dfa47b6edfb2
http://github.com/moodle/moodle/commit/0ac97084faa3d0114b8cb6d69332dfa47b6edfb2
+ 2.5 en [pluginname,tinymce_spellchecker]