softened, clarified language on empty list listings page @jrouly

bookshare/trades/templates/list_listings.html

@@ -60,9 +60,9 @@ SRCT Bookshare • Latest Listings
     <div class="col-md-10 col-md-offset-1 text-center">
       <div class="panel panel-warning">
         <div class="panel-body">
-          <h3>There aren't any books in the database!</h3>
+          <h3>There aren't any open listings in the database right now!</h3>
           <p>
-            Looks like you'll be the first to <a href="{% url 'create_listing' %}">create one</a>!
+            You can be the first to <a href="{% url 'create_listing' %}">create one</a>.
           </p>
         </div>
       </div>