Add a generator to MysqlRedFam to retrieve redfams from db by status

mysqlred.py

@@ -264,3 +264,20 @@ article7 ) VALUES ( ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? );'
         type( self )._cached_update_data.append( ( red_page_id, heading,
                                                    beginning, ending, status,
                                                    self.__fam_hash ) )
+    
+    def get_by_status( self, status ):
+        """
+        Generator witch fetches redFams  with given status from DB
+        """
+        
+        cursor = type( self ).connection.cursor( mysqldb.DictCursor )
+        
+        cursor.execute( 'SELECT * FROM `red_families` WHERE `status` = ?;',
+                        ( status, ) )
+        
+        while True:
+            res = cursor.fetchmany( 1000 )
+            if not res:
+                break
+            for row in res:
+                yield row