MDL-45645 mod_lti Add custom LTI request parameter ext_user_username
MDL-45445 events: trivial changes
MDL-45445 events: added missing 'relateduserid' validation
MDL-45445 events: added missing 'other' validation
MDL-45445 events: documented the additional validation
MDL-45445 events: added '(optional)' to event params where applicable
MDL-28420 enrol_database: Allow use of remote hidden field to specify non-enrolled 'Other User' creation
MDL-46079 Restore: Can run out of memory in get_records call
Merge branch 'MDL-45445_master' of https://github.com/markn86/moodle
MDL-43365 lib: added better means of renaming classes for autoloading

I've added a better means of renaming classes for autoloading and
handling the deprecation of the original class name.
This system records renamed classes in db/renamedclasses.php and
when a renamed class is requested a debugging notice is printed
and a class alias is created so that the calling code both works
and is informed of the deprecation.
MDL-43365 lib: converted text and plugin deprecated classes to new scheme

Four core library classes renamed for autoloading with deprecated stubs
have been converted to the new scheme for autoloading.
They are:

 * textlib
 * collatorlib
 * plugin_manager
 * plugininfo_base

These will be removed in 2.9 by MDL-46124
Merge branch 'MDL-45645_LTIUsernameParam' of https://github.com/moodlerooms/moodle
Merge branch 'MDL-46079-master' of https://github.com/sammarshallou/moodle
Merge branch '43365-28' of git://github.com/samhemelryk/moodle
Merge branch 'MDL-28420_master' of https://github.com/jrchamp/moodle
MDL-46031 output: remove leftover line
MDL-43835 behat: Fixed matches for select form field
MDL-43835 behat: Fixed backup behat test

Disabling section, disables all checkboxes in section,
So we don't have to unset them manually
MDL-43835 behat: Added new step to set field with xpath defined
MDL-43835 behat: Use proper step for navigation expansion