Add support for PostgreSQL 9.5's IMPORT FOREIGN SCHEMA

[InfoSec812]

FDW in PostgreSQL 9.5 supports automatically importing the schema from the foreign data source. It would be awesome to add logic to JDBC_FDW in order to have this happen with well-known database engines like Oracle/MSSQL/MySQL/etc...

[ArturFormella]

+1 Possible dup of #23