Add SQL logging to PostgreSQL and SQLite

[hiteshjasani]

Changes will write sql statements out to STDOUT to help with debugging.

Sample usage:

import db_postgres

db_postgres.SQL_LOGGING = true

...
Exec(db, sql"create table tbl1(id serial primary key not null, one varchar(10), two smallint)", [])

# [create table tbl1(id serial primary key not null, one varchar(10), two smallint)]

[Araq]

I won't accept this. The Nimrodic way is entirely different: Write a macro that reads in the module, parseStmt it, iterates over any operations with a TSql argument and wrap that via an overloaded op. Then import db_sqlite_log instead of db_sqlite to get the logging version.