define roles: MDL-16966 etc. polishing the new roles UI following a meeting with Martin.

* 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.

lib/accesslib.php

@@ -157,8 +157,8 @@ define('RISK_DATALOSS',    0x0020);
 define('ROLENAME_ORIGINAL', 0);// the name as defined in the role definition
 define('ROLENAME_ALIAS', 1);   // the name as defined by a role alias
 define('ROLENAME_BOTH', 2);    // Both, like this:  Role alias (Original)
-define('ROLENAME_ORIGINALANDSHORT', 0); // the name as defined in the role definition and the shortname in brackets
-define('ROLENAME_ALIAS_RAW', 1);   // the name as defined by a role alias, in raw form suitable for editing
+define('ROLENAME_ORIGINALANDSHORT', 3); // the name as defined in the role definition and the shortname in brackets
+define('ROLENAME_ALIAS_RAW', 4);   // the name as defined by a role alias, in raw form suitable for editing
 
 $context_cache    = array();    // Cache of all used context objects for performance (by level and instance)
 $context_cache_id = array();    // Index to above cache by id