Cosmetic change to web page: "heat map" instead of "heatmap"

Rails/app/views/assays/_form.html.erb

@@ -128,7 +128,7 @@
     </div>
   </li>
   <li>
-    <h3><span data-tooltip="Select value ranges for the heatmaps for easier comparison between experiments.">Heatmap options</span></h3>
+    <h3><span data-tooltip="Select value ranges for the heat maps for easier comparison between experiments.">Heat map ranges</span></h3>
     <div class="field">
       <%= f.label "Enter the range for the achieved growth on log scale." %><br />
       <%= f.text_field :totg_min, :size => '5' %>