refactor classes, don't show a trailing whitespace

lib/best_in_place/helper.rb

@@ -31,14 +31,13 @@ def best_in_place(object, field, opts = {})
         value = fieldValue ? opts[:collection][1] : opts[:collection][0]
         collection = opts[:collection].to_json
       end
+      classes = ["best_in_place"]
       unless opts[:classes].nil?
         # the next three lines enable this opt to handle both a stings and a arrays
-        classes = []
         classes << opts[:classes]
-        classes = classes.flatten
-        opts[:classes] = classes.join(' ')
+        classes.flatten!
       end
-      out = "<span class='best_in_place #{opts[:classes]}'"
+      out = "<span class='#{classes.join(" ")}'"
       out << " id='#{BestInPlace::Utils.build_best_in_place_id(real_object, field)}'"
       out << " data-url='#{opts[:path].blank? ? url_for(object) : url_for(opts[:path])}'"
       out << " data-object='#{opts[:object_name] || BestInPlace::Utils.object_to_key(real_object)}'"