MDL-19124 Continued misc user profile cleanups

- 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)

user/index.php

@@ -143,10 +143,13 @@
     $PAGE->set_title("$course->shortname: ".get_string('participants'));
     $PAGE->set_heading($course->fullname);
     $PAGE->set_pagetype('course-view-' . $course->format);
+    $PAGE->add_body_class('path-user');                     // So we can style it independently
     $PAGE->set_other_editing_capability('moodle/course:manageactivities');
 
     echo $OUTPUT->header();
 
+    echo '<div class="userlist">';
+
     if ($isseparategroups and (!$currentgroup) ) {
         // The user is not in the group so show message and exit
         echo $OUTPUT->heading(get_string("notingroup"));
@@ -884,6 +887,8 @@
         echo $OUTPUT->container(html_writer::link($perpageurl, get_string('showall', '', $matchcount)), array(), 'showall');
     }
 
+    echo '</div>';  // userlist
+
     echo $OUTPUT->footer();
 
     if ($userlist) {