MDL-38347 - Calendar - Fixing arrow output on Android devices
MDL-28124 admin/tool/customlang: Changed page layout from 'standard' to 'report'.
MDL-39760: mod_assign: Make submit_for_grading accept submission as parameter
MDL-39760: mod_assign: Add few more callback methods.

Adds lock, unlock and release_to_draft. All of them accept single parameter -
an assign_submission record.
MDL-40264 fix essay handling of zero-string response

Fixes an inappropriate behavior of the is_complete_response() function
for the Essay question type, which caused the string "0" to be
inappropriately marked as an incomplete response.

Also adds a set of unit tests for the Essay question type's
is_complete_response.
MDL-34610 remove legacy IE CSS. It breaks form layout
MDL-40255 theme_boxxie/theme_formfactor: Added block-region class to layout files to enable dnd file uploader to work.
Merge branch 'MDL-28124_M23' of git://github.com/lazydaisy/moodle into MOODLE_23_STABLE
Merge branch 'wip-MDL-38347-stable23' of git://github.com/phalacee/moodle into MOODLE_23_STABLE
MDL-38347 fixed whitespace
Merge branch 'MDL-39760-MOODLE_23_STABLE' of https://github.com/lucisgit/moodle into MOODLE_23_STABLE

Conflicts:
	mod/assign/locallib.php
MDL-40250 phpunit: Add unit tests for core_files_external::upload()
MDL-40258: Fixed invalid json string error in file-picker
MDL-40200 Administration: Return the invalid user message and stop there

To avoid adding duplicate code, 'invalid user' and 'user deleted' checks
have been merged together.

Conflicts:
	user/profile.php
Merge branch 'MDL-40255_M23' of git://github.com/lazydaisy/moodle into MOODLE_23_STABLE
Merge branch 'MDL-34610_23' of git://github.com/timhunt/moodle into MOODLE_23_STABLE
Merge branch 'MDL-40264-m23-essay-zero' of git://github.com/ktemkin/moodle into MOODLE_23_STABLE
Automatically generated installer lang files
Merge branch 'install_23_STABLE' of git://git.moodle.cz/moodle-install into MOODLE_23_STABLE
weekly release 2.3.7+