Changes to the RE2 module

• Queries are guaranteed to fail if invalid regular expressions are passed.

Changes to the Digest module

• Added the Digest::Sha512 function.

Changes to the DateTime module

• Changed the return type for DateTime::ToSeconds(Interval) from Int32 to Int64.
• Changed the argument type for DateTime::IntervalFromSeconds from Int32 to Int64.

Changes to the SELECT syntax

• You can now explicitly specify DISTINCT for UNION.
• Added INTERSECT [DISTINCT|ALL] implementation.
• Added EXCEPT [DISTINCT|ALL] implementation.