login database name is used for presto_catalog and presto_schema if the parameters are empty in prestogres.conf
reverted patches of pool_where_to_send function before implementing new architecture
Implemented partial query rewriting using PostgreSQL lexer.

* Added support for cursors. DECLARE starts a query on Presto, FETCH
  fetches results, and CLOSE deletes the query from Presto.
* Added support for multi-statement queries
* Added support for INSERT INTO ... VALUES and INSERT INTO ... SELECT
  added since Presto 0.75
* Added support for CREATE TABLE and CREATE TABLE ... AS SELECT added
  since Presto 0.73.
* Added support for EXPLAIN.
* BEGIN command in multi-statement query actually runs on PostgreSQL
  and returns "BEGIN" notice message to clients to be compatible with
  postgresql-jdbc with setAutoCommit(false) mode.
rewrite_error_query runs rollback to propagate error message even in multi-statement query with heading BEGIN command