v1.30.1

Added

• Every custom column is now filterable. A filter control is generated
  automatically for each one - a dropdown offering All plus the column's
  own values for a dropdown-type column, or a substring text box for a
  text-type column - and it appears or disappears as you create or delete
  columns. It combines with every other filter (search, year, etc.) the same
  way they combine with each other.