revise progress persistent file format to reduce file size.
example: print out number of rows consumed

1. taos_consume block for evev
2. taos_fetch_block returns 0 in subscription

Malloc memory to store Lua state and callback function from Lua. Connector can support multiple connection by this way.
Memory will be freed when connection isn't established successfully or connection is closed by lua call. Stream content
in Lua is not the same one with stream content in connector.

A loop in test code do the job for continuous query. record is inserted between query actions.