[#32881] All Tags view does not show Intro images

All Tags view expected image params to be stored as a separate JRegistry object -- instead these are lumped into params.  default_items.php also had problems with incorrect and missing param names.

Added 'float_intro' field to config to prevent the div around the image from having class="pull- item-image" (a value is expected as the tag param includes a JGLOBAL option).  Default value is none, and if set to none, 'pull-' is not included in the class.

This does add a new language string.

How do we handle the sql for adding the new config field?
Tracker: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=32881
You can directly use `$item->params['image_intro']`