- fixed user styles in base theme
    - added new divs for better control on user profile and user index pages
    - reduced data on course user profiles down to minimum
    - removed user/tabs.php completely and all uses of it
    - changed default user icon pix to something very bland (bye bye smiley cake)

MDL-21655 big scary enrolment and roles improvements - see tacker for list of changes, includes other minor fixes too

* class html_component does not exist any more
* class html_table rendered via html_writer::table()
* html_table, html_table_row and html_table_cell have public $attributes property to set their CSS classes
* dropped rotateheaders feature, should be added again after more research of possible ways (<svg> is not nice IMHO)
* dropped possibility to define CSS classes for table heading, body and footer - can be easily done and better done using just table class and context

MDL-21233 moodle_url improvemewnts, code simplification, more diagnostics; fixed several regressions

MDL-21217, MDL-21198 simplified/improved outputlib help icon related apis + several fixed regresions

MDL-20204 first batch of major theme changes, some regressions are still there, expect more changes and improvements soon; see tracker for details and list of subtasks

Moved $action argument from arg5 to arg2

MDL-19787 upgraded calls to print_table, print_single_button, print_user_picture, print_container* and notice_yesno

even non-course and sticky blocks.

The parent context is block_instances.parentcontextid.

The block context should be used for checking permissions directly
related to the block, like moodle/block:view or moodle/site:manageblocks.

However, if the block is displaying information about the current page,
for example the participants block showing who 'here', then it may be
better to use the context of the page where the bloack is appearing -
in other words $this->page->context - to check permissions about the
user's ability to see participants here.

Or, if the block is displaying something stronly related to courses,
for example, a course meny block, the block should probably use the
context for $this->page->course to check permissions.

There is a new implementation of require_js in lib/deprecatedlib.php,
based on $PAGE->requires.

There were a few other recently introduced functions in lib/weblib.php,
namely print_js_call, print_delayed_js_call, print_js_config and
standard_js_config. These have been removed, since they were never in
a stable branch, and all the places that used them have been changed
to use the newer $PAGE->requires->... methods.

get_require_js_code is also gone, and the evil places that were calling
it, even though it is an internal function, have been fixed.

Also, I made some minor improvements to the code I committed yesterday
for MDL-16695.

All that remains is to update all the places in core code that are
still using require_js.

(This commit also fixes the problem where the admin tree would not
start with the right categories expanded.)

That was becuase not enough information was being passed in for the blocks editing controls to construct the right URL to reload the page.

It is also now possible for admin external pages to add some UI next to the turn blocks editing on/off button. For example, when you are editing the list of course catgories, the turn editing off button is now in the right place.

* Move the show/hide advanced button a bit down the page.
* Improve save button caption when creating a role.
* Don't show defaults on the basic define roles screen.
* Explain the background shading on the advanced roels screen.
* Fix the problem with the risks link to Moodle docs.
* Help icon by the permissions column heading.
* Tables with rotated <th>s, make them vertical-align: bottom.
* Rename explain.php and explainhascapability.php to check.php and explain.php
* Tool tips on the number headers in the explain table.
* Explain table - role names were missing.
* Allow link_to_popup_window to work with full URLs.

I have collected code that used to be in lib/adminlib.php, lib/accesslib.php and user/selector/lib.php into a new admin/roles/lib.php file.

And I added standard GPL and Moodle comments to all the files in admin/roles.

role assign: MDL-13325 when assigning roles inside front page activites, list all users as potential users.