MDL-42625 behat: Wrapping select an option extra actions in a try & catch

To select an option is specially painful, every browser
behaves differently and phantomjs just joined the party
throwing "Element does not exist in cache" random
exceptions that we need to catch.
MDL-33925: auth_imap: add self-signed cert support
Automatically generated installer lang files
Merge branch 'install_master' of git://git.moodle.org/moodle-install
weekly release 2.7dev
MDL-41062 gradebook: remove sortorder duplicates

* Upgrade function to remove duplicates from the grade item duplicates
  column. Duplicates were causing sorting to fail in some cases.
* Add some unit tests which simulate sort order duplicate data and
  verify that they have been removed.
MDL-41062 WIP: fixes for freds comments