Significant string changes:
* multiple strings in core_hub - 'Publish' changed to 'Share' plus other
wording improvements to avoid misunderstandings
* errorretrievingkey in message_airnotifier - improved wording and
removing reference to Moodle.org
* enddate_help and courseduration_desc in core - clearer wording
explaining what the date actually does
* restore:viewautomatedfilearea in core_role - changing wording to match
the behaviour
* dropzones_help in qtype_ddmarker - improved wording
* autologinkeygenerationlockout in tool_mobile - updated error message
* configallowemailaddresses in core_admin - clearer description
* subscriptionmode_helpin mod_forum - removing misleading sentence about
subscription mode changes not affecting existing users
Zig Tan