Improvement to make removeClass() pass.

Author: jesseleite

src/AdamWathan/Form/Elements/Element.php

@@ -55,7 +55,13 @@ public function removeClass($class)
         if (! isset($this->attributes['class'])) {
             return $this;
         }
+
         $class = trim(str_replace($class, '', $this->attributes['class']));
+        if ($class == '') {
+            $this->removeAttribute('class');
+            return $this;
+        }
+
         $this->setAttribute('class', $class);
         return $this;
     }