Procedure support improvements

Exception in thread "main" org.postgresql.util.PSQLException: ERROR: invalid transaction termination

2) Output parameters are not mapped as parameters, and app code cannot use registerOutputParameter or getInt() style retrieval. Instead, outputs are left in the result set and app code must retrieve the result and pull, creating a big difference between how Procedures and Functions are invoked.

I propose improving support for procedures. Either:

(1) add support for "CALL proc()" to be treated as a routine invocation so that output parameters can be registered, no begin transaction is silently sent from driver, and calling a procedure and calling a function would be very similar (only differing in function still using the {call} escape syntax.

or

(2) change the {call} syntax to optionally support procedures. {? = call} would still be mapped to functions. Add a connection setting to control this change, and make default false, so that default stays backwards compatible with pre pg11 functionality.

Thoughts?