MDL-36778 course - prevent undefined index warnings

When logged in as a guest the mform didn't set userid.
MDL-30961 get_course_contents: returned activity name should not be check against PARAM_TEXT, it could be anything
MDL-36755 blocks: the course overview block can only be added to the My Moodle page so removing unnecessary addinstance cap
MDL-35404 question export: make it work with slasharguments off.

Thanks to Brian King for working out the problem and how to fix it. I am
just committing his patch.
MDL-36946 theme Use server default theme before standard
MDL-36650 don't change question timecreated or timemodified on restore.
MDL-36732 Cloze qtype: review marks should not depend on feedback.

The various review options should be independent.
MDL-36845 excel export: don't output invalid sheet names.

We should clean any proposed worksheet name, to remove the characters
that Excel does not allow.
MDL-36897 quiz: redirect teachers from summary to review page.

There is already logic like this at the top of attempt.php. If the
teacher arrives at one of these pages for a student's attempt, for
example by clicking a link in the logs, then they should be redirected
to the review page to see the students attempt in its current state.
MDL-36942 xml question import: don't add spaces.

They are not necessary anyway, there is a \n character at the end of
each line.

Thanks to Richard Lobb for fining the problem and how to fix it.
MDL-36954 question bank: stop centring question name.

This was a regression caused by MDL-21625. These CSS changes
put the display back to how it was, while leaving the table
cell as a TD  for accessibility.
MDL-36341 calendar: fixed JS bug with popup node setter
MDL-35593 core_webservice_get_site_info returns version number set to PARAM_TEXT and PARAM_FLOAT
MDL-35816 - File picker - Adding ALT attributes to the icons of the file picker
MDL-29805 add REQUIRE_CORRECT_ACCESS define + return error code when AJAX_SCRIPT fails
MDL-36110 - Blocks - Community finder icon alt attribute is now empty
MDL-3941 auth/cas auth/ldap enrol/ldap Add support for LDAP-TLS.

Credit goes to Chris Bandy for proposing the initial patch.
MDL-35979 - Commenting - Adding an empty alt attribute to the javascript generated delete icon for comments
MDL-36840 Set course.format to 'site' for site-course
MDL-37020 auth_shibboleth: check if target variable is actually set