Top-level statement changes

Added support for MATERIALIZE.

Added support for COMBINE.

Built-in function changes

Added Decimal support to ListFromRange.
Added AsErased and PeekErased for value type erasure.

Changes to yt pragma defaults

The yt.ConvertDynamicTablesToStatic="join" pragma is enabled by default.
To roll back this change in your query, add pragma yt.ConvertDynamicTablesToStatic="disable".