Fixed some styles/layout on the test add page

assets/styles/nardah.scss

@@ -71,3 +71,8 @@ textarea{
   margin-top: 15px;
   padding: 15px 20px;
 }
+
+#benchmark-selector{
+  $max-width: 100%;
+  $min-height: 100px;
+}

views/test/add.twig

@@ -14,25 +14,14 @@
   <div class="twelve columns">
     <form action="{{ url_for('test.add') }}" method="POST" class="u-full-width">
       <div class="row">
-        <div class="four columns">
+        <div class="six columns">
           <label>
             Test title:
             <input class="u-full-width" type="text" name="test_title" placeholder="My new test">
           </label>
         </div>
 
-        <div class="four columns">
-          <label>
-            Benchmarks:
-            <select class="u-full-width" name="test_benchmarks" multiple>
-              {% for b in benchmarks %}
-                <option value="{{ b.id }}">{{ b.name }}</option>
-                {% endfor %}
-            </select>
-          </label>
-        </div>
-
-        <div class="four columns">
+        <div class="six columns">
           <label>
             Hardware component:
             <select class="u-full-width" name="test_component">
@@ -44,6 +33,19 @@
         </div>
       </div>
 
+      <div class="row">
+        <div class="twelve columns">
+          <label>
+            Benchmarks:
+            <select id="benchmark-select" class="u-full-width" name="test_benchmarks" multiple>
+              {% for b in benchmarks %}
+                <option value="{{ b.id }}">{{ b.name }}</option>
+                {% endfor %}
+            </select>
+          </label>
+        </div>
+      </div>
+
       <div class="row">
         <div class="twelve columns">
           <label>