MDL-40769 usability: new icons for TinyMCE in svg and png formats
MDL-40770 TinyMCE - Implement new icons
MDL-40769 usability: additional icons for TinyMCE in svg and png formats
MDL-40770 TinyMCE - Further changes to implement new icons
MDL-40769 usability: last bit of icons for TinyMCE in svg and png formats
MDL-40770 TinyMCE - Implementing new icons
MDL-41385 usability: new non-default icons for TinyMCE in svg and png formats

Conflicts:

	lib/editor/tinymce/tiny_mce/3.5.8/themes/advanced/skins/moodle/img/delete.png
	lib/editor/tinymce/tiny_mce/3.5.8/themes/advanced/skins/moodle/img/delete.svg
	lib/editor/tinymce/tiny_mce/3.5.8/themes/advanced/skins/moodle/img/spellcheck.png
	lib/editor/tinymce/tiny_mce/3.5.8/themes/advanced/skins/moodle/img/table.png
	lib/editor/tinymce/tiny_mce/3.5.8/themes/advanced/skins/moodle/img/table.svg
MDL-40770 TinyMCE - Final Icon implementation
MDL-9873 questions Set question text field to required.

After much discussion, it was decided that the damage done by not
not setting question text (student goes to take test and sees nothing)
is more of a problem then the use cases where teachers want empty
questions (inputing paper tests). In those cases, they will need
to add something like a period to the question text field.
MDL-41912 editor_atto: Padding for editable area
MDL-41996: Don't show the Review Attempt link if no attempts exist.
MDL-32592 enrol_imsenterprise: fix error when category not defined

thanks to Henrik Thorn for the fix
MDL-41989 Atto - Improving usability for non-touch devices
MDL-42003 mod_forum: Convert handlers to observers
MDL-42004 enrol_cohort: Convert handlers to observers
MDL-41039 mod_quiz: Replace events_trigger to new events
MDL-41039 mod_quiz: Renaming event to attempt_becameoverdue
MDL-39653 enrol_imsenterprise: only mail admins on change

The existing beavhiour was sending useless emails to admins and
generating warnings.

Thanks to Matthew Orlando for the suggested fix.
MDL-42001 mod_chat: Transforming handlers to observers
MDL-42021 events: Debug message when objecttable set without an objectid