Slideshow field changes.  #1331

Removed body, added description.  Desc and headline are 128 characters (erring on the side of too many letters here.  If it looks bad users can trim).  Both have been wrapped in text-and-controls div.

Changed media to imagefield_crop.  Preset crop ratio is the same as what has been provided for classic theme's slideshow.

@jmburnz, because of these field changes, you'll have to delete all slideshow_image nodes in order to revert the feature.  Sorry about that.

Editing the widget filters out dead nids.  It's harmless to have extras in there, but there's no reason not to clean them up periodically.

An empty links field defaults to a URL of #.  No more stupid link there.
Merge branch 'SCHOLAR-3.x' of github.com:openscholar/openscholar into SCHOLAR-3.x