Some improvements/fixes for search.  
-map extent changes are queued so that multiple changes in a short time
frame fire only one search.
-duplicate search queries are detected so that consecutive duplicate
queries don't fire multiple searches (pressing the search button over
and over without changing any params fires only one search)
-the keyword field in advanced search works properly now.

clean-up of solr.js;  a lot of cruft had accumulated.

Hover over cart options now highlights layers correctly.

Some css fixes:  
-borders for table cells in the preview pane are no longer white.
-z order for modal dialog mask fixed