Fixed detection of truthyness of null values.

Author: smuuf

src/helpers/Common.php

@@ -4,6 +4,7 @@
 
 use \Smuuf\Primi\Structures\StringValue;
 use \Smuuf\Primi\Structures\BoolValue;
+use \Smuuf\Primi\Structures\NullValue;
 use \Smuuf\Primi\Structures\NumberValue;
 use \Smuuf\Primi\Structures\ArrayValue;
 use \Smuuf\Primi\Structures\Value;