MDL-40515: report_log: List activities in optgroups

Prevents users from generating reports on invalid values

Change-Id: If358fa06c8dadd33bb2875ea54ab4bce97b16aff
MDL-39489 behat: Updating to 2.6 moodlehq/behat-extension tag

Also solving new problem after Behat
2.5 upgrade.
MDL-38664 Lesson mod: fixed re-attempt unseen page
MDL-38664 Lesson mod: code improvement for lesson re-attempt page
MDL-42402 EditPDF: CSS Improvements for editing toolbar.

The main change here is to prevent the default rendering of a select list for the page
selector, so that it looks more consistent with the rest of the toolbar on different
browsers/os combinations.

This is done with some vendor specific css rules targeting webkit, mozilla and ie.

There are also some minor tweaks to vertically align the images in the buttons and reduce the padding
above and below the toolbar.
MDL-38850: Fixed Horizontal bar issue in lesson
MDL-35146 mod_wiki: fixed issue where pages for deleted groups caused an error on restore
MDL-35146 mod_wiki: fixed variable typo and altered code to conform to Moodle guidelines
MDL-42583 events: Fix snapshot issues with note events
MDL-42633 messages: Fix alternate name warnings when a message popup is shown
MDL-40722 Theme: Add back a more-specific selector for some blocks

This addresses an issue on narrow devices whereby block width is
incorrectly overridden with a more-specific selector.
MDL-42664 Fix the filter_manager instantiation

For legacy reasons, the $CFG->perfdebug uses values 7 for disabled and 15 for
enabled. Because of this typo, Moodle has always created instance of the slower
performance_measuring_filter_manager instead of the standard filter_manager,
regardless the perfdebug setting.
MDL-42663 mod_lesson: Move definitions to show_clock()

Seems that the required data is not always set
before timer.js is included.
MDL-42521 mod_feedback - Feedback does not show line graphs in Clean theme
Merge branch 'MDL-38850' of git://github.com/rwijaya/moodle
Merge branch 'MDL-42583-master' of git://github.com/ankitagarwal/moodle
Merge branch 'MDL-42664-performance_measuring_filter_manager' of git://github.com/mudrd8mz/moodle
Merge branch '42452-26' of git://github.com/samhemelryk/moodle
Merge branch 'MDL-42663_master' of git://github.com/dmonllao/moodle
Merge branch 'MDL-42521_master' of git://github.com/grabs/moodle