This fixes the image display in IE7 with the disadvantage that now in
IE7 with images disabled the text won't be displayed anymore.

This makes the pagetools in non-hover/static/active-mode use another
image replacement technique that falls back to the text when images are
disabled. Furthermore this fixes the :focused-display in IE7 by using
:active, too.

For some reason without position: relative the search button is hidden
in rtl languages.

The previous fix in e38f3066 fixed this
bug only in tb_formatln.

This adds $INPUT in all places where it was still missing and available.
$INPUT is now also used in places where using $_REQUEST/... was okay in
order to make the code consistent.

force screen_mode to string type (IE returns a number which is always triggering the default option in the following switch/case block

tidy up authtype setting class (incl. fix issue with auth change/logoff occurring when only one auth plugin is enabled and other settings are updated)

setting type read from metadata eqaul to empty string is default 'setting' class (a textarea), everything else should be a existing class otherwise 'setting_no_class' is loaded