pgsql: Add INTERVAL items: > * Add support for ANSI time INTERVAL

Log Message:
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Add INTERVAL items:

* Add support for ANSI time INTERVAL syntax, INTERVAL '1 2:03:04' DAY TO SECOND
* Add support for ANSI date INTERVAL syntax, INTERVAL '1-2' YEAR TO MONTH
* Process mixed ANSI/PG INTERVAL syntax, and round value to requested precision

184a188,189

Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1 year' AS INTERVAL
MONTH), and this should return '12 months'

Modified Files:
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pgsql/doc:
TODO (r1.1473 -> r1.1474)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1473&r2=1.1474)