correction orIsNull and orIsNotNull

Author: mathieu-noel

src/Request.php

@@ -699,6 +699,10 @@ public function __toString()
      */
     public function __call( $name, $arg )
     {
+        if($this->where === null)
+        {
+            $this->where = new Where();
+        }
         if( method_exists($this->where, $name) )
         {
             if( $name === 'in' && is_callable($arg[ 1 ]) )

src/Where.php

@@ -347,7 +347,7 @@ public function isNull( $column, $condition = '===', $bool = 'and',
      */
     public function isNotNull( $column )
     {
-        $this->isNull($column, '!==', 'and', true);
+        $this->isNull($column, '===', 'and', true);
         return $this;
     }
 
@@ -373,7 +373,7 @@ public function orIsNull( $column )
      */
     public function orIsNotNull( $column )
     {
-        $this->isNull($column, '!==', 'or', true);
+        $this->isNull($column, '===', 'or', true);
         return $this;
     }