[#31675] Remove last uses of JRequest in Joomla

Combined with #3677 this should remove all instances of JRequest from Joomla - which paves the way for it's removal in J4.0 :D

http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=31675

Almost, except for the big flashing
> Parse error: syntax error, unexpected ')', expecting '(' in /.../administrator/components/com_banners/controllers/tracks.raw.php on line 92

Make it `$form  = $input->get('jform', array(), 'array');` and it will work :smiley: