Fixes bug when escaping boolean values in postgres
Fixes bug on Model.sync (postgres) when property has default value (using wrong path to escape method)
Fixes DDL drivers creating duplicated field in reversed hasOne associations
Changes Model instanciation to extend association properties
Adds tests for Amazon Redshift

Redshift is based on Postgres driver. The only difference for now is
that it can't use RETURNING keyword syntax and so it has to do a second
query after INSERT to retrieve the last insert id.
Changes Makefile to include Redshift driver test
Fixes "bug" in Redshift. Sometimes INSERT id is not necessary (hasMany 3rd tables)