small bugs in element chart

Author: dbarzin

src/PhpWord/Style/Chart.php

@@ -331,6 +331,7 @@ public function setDataLabelOptions($values = array())
                 $this->dataLabelOptions[$option] = $this->setBoolVal($values[$option], $this->dataLabelOptions[$option]);
             }
         }
+        return $this;
     }
 
     /*
@@ -378,7 +379,7 @@ public function getCategoryLabelPosition()
      */
     public function setCategoryLabelPosition($labelPosition)
     {
-        $enum = array('nextTo', 'low', 'high');
+        $enum = array('none', 'nextTo', 'low', 'high');
         $this->categoryLabelPosition = $this->setEnumVal($labelPosition, $enum, $this->categoryLabelPosition);
 
         return $this;