move all exception declaration to their own file

lib/Connection.php

@@ -52,22 +52,6 @@ class Connection
     final private function __clone() {}
 }
 
-class SqlException extends Exception
-{
-    private $query;
-
-    public function __construct($message = "Sql Error", $query = "")
-    {
-        $this->query = $query;
-        parent::__construct($message, 0);
-    }
-
-    public function getSqlError()
-    {
-        return $this->getMessage().' while executing: '.$this->query;
-    }
-}
-
 class OdbcResultSet implements Iterator, ArrayAccess
 {
     public $length;