Since changing to rg=0 we make extensive use of $_SESSION and $HTTP_SESSION_VARS...

Since changing to rg=0 we make extensive use of $_SESSION and $HTTP_SESSION_VARS. Because of this session_register, session_unregister, and session_is_registered should NOT be used (see the PHP manual at php.net). They are buggy over different PHP versions anyway. Now when changing a session var using the custom 'sq' version of these functions (all located in global.php) the superglobal array is accessed directly. This fixes the problem with corrupted objects in the session. Tested with 4.1.2 rg=0 and 1.

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@3782 7612ce4b-ef26-0410-bec9-ea0150e637f0