General Changes

• Added arbitrary() aggregation function.
• Allow using all Aggregate Functions as Window Functions.
• Support specifying window frames and correctly implement frames for all Window Functions.
• Allow approx_distinct() aggregation function to accept a standard error parameter.
• Implement least() and greatest() with variable number of arguments.
• ARRAY is now comparable and can be used as GROUP BY keys or in ORDER BY expressions.
• Implement = and <> operators for ROW.
• Fix excessive garbage creation in the ORC reader.
• Fix an issue that could cause queries using row_number() and LIMIT to never terminate.
• Fix an issue that could cause queries with row_number() and specific filters to produce incorrect results.
• Fixed an issue that caused the Cassandra plugin to fail to load with a SecurityException.