Allow nested condition groups

XML 쿼리에서 <conditions><group> 안에 <group> 태그를 또 쓸 수 있도록 허용함.
이제 WHERE (a AND (b OR (c AND d))) 이런 조건을 작성할 수 있음.

classes/db/queryparts/condition/ConditionGroup.class.php

@@ -105,11 +105,24 @@ class ConditionGroup
 	{
 		$args = array();
 		foreach($this->conditions as $condition)
-		{
-			$arg = $condition->getArgument();
-			if($arg)
+		{
+			if($condition instanceof ConditionGroup)
+			{
+				foreach($condition->getArguments() as $arg)
+				{
+					if($arg)
+					{
+						$args[] = $arg;
+					}
+				}
+			}
+			else
 			{
-				$args[] = $arg;
+				$arg = $condition->getArgument();
+				if($arg)
+				{
+					$args[] = $arg;
+				}
 			}
 		}
 		return $args;