Postgresql - Convert Boolean & Integers to 'native' types

Hi,

This PR fixes a long standing issue with the pgsql extension and native boolean & integer types. (https://bugs.php.net/bug.php?id=29213, https://bugs.php.net/bug.php?id=47051)

Currently, boolean columns are returned as the strings 't' and 'f'; and integers are returned as strings.

To prevent backwards compatibility issues, the change is gated by the php.ini settings `pgsql.convert_boolean_type` and `pgsql.convert_integer_type`.

I'm making this requests against PHP-5.4, as it's backwards compatible - and if successful, I'll merge/port it forwards to 5.5, 5.6/devel