MDL-42815 Backup/restore: Error saving files - log messages unhelpful

This commit contains three changes in the three files:
1. A bug in the backup process meant that anything logged after a
   certain point did not appear in the on-screen display of the
   backup log, because the logger was serialised and deserialised
   but display code referred to the old version. Changed so that
   code retrieves new object.
2. Add more information to backup log when there is a missing file.
3. Add more information to restore log when there is a missing file
   (and remove existing code duplication of the current message).

The 'missing file' situation is one that generally shouldn't occur in
normal usage, but when it does happen, it is useful to have full
information about the file.
MDL-43071 assign: Fix offline grades import for scale grading.
MDL-42487: Forced userprofile dl style to be displayed: inline-block.
MDL-43150 tinymce_managefiles: fixed unattractive background
MDL-43202 JavaScript: Migrate moodle-course-toolboxes to user Shifter
MDL-38775 JavaScript: Migrate moodle-form-shortforms to Shifter
MDL-38776 JavaScript: Migrate moodle-form-showadvanced to Shifter
MDL-40517 deprecatedlib: remove functions

* Removed functions which were throwing fatal errors
* Fixup navmenu comment, as it hasn't been throwing a fatal error, it
  shouldn't be removed as part of this issue yet. (Although if you are
  still using this function, you are crazy and should thank me ;-)).
MDL-37517 testing: remove deprecated classes
MDL-43215 core_webservice: retrieve all user name fields when adding a token
MDL-42174 More behat tests for filepicker
MDL-42174 behat: deprecate upload file to filepicker step in favour of filemanager
MDL-42174 behat: change word filepicker to filemanager in step definitions
MDL-43131 qbank: Fix show question text when first viewing.

When you followed the link to the question bank, the checkbox for the
"Show question text in the question list" option correctly reflected the
user's preference, but what was actually shown in the question bank did
not.
MDL-43082 Themes IE 9 Compatibility View doesn't support SVG.
MDL-31625 fix multiple global search-replace issues

Includes following fixes:
* support for MS SQL Server
* optional trimming of of oversized VARCHAR fields
* conversion to forms library
* full localisation
* other cleanup
MDL-31410 always send 200 in PayPal IPN response and hide all errors
MDL-41030 behat: Dock blocks compatible with both selenium and phantomjs
MDL-41030 Behat: Add support for waiting for javascript

This is so that phantomjs (which runs faster than selenium) can pass the tests.
MDL-41030 JavaScript: Convert remaining YUI2 IO calls to YUI3