dendro v0.3.3

Added

• ColumnFilter::projects(stream), default true: a stream it returns
  false for is copied as it is by a keep_columns pass, sealed segments
  byte for byte and its tail unprojected. For a companion stream whose
  columns a field-by-field filter cannot tell from the data's.

Fixed

• project_segment_columns keeps the source file's key-value metadata
  (all but ARROW:schema, which the writer writes for the projected
  schema). It wrote the projection with only the caller's properties, so a
  segment marked by its caller (a layout, a list of what its rows refer to)
  lost the mark and could read back as another kind of segment.