0.20.5

Added

• Existential sizes can now be explicitly quantified in type
  expressions (#1308).

• Significantly expanded error index.

• Attributes can now be numeric.

• Patterns can now have attributes. None have any effect at the
  moment.

• futhark autotune and futhark bench now take a --spec-file
  option for loading a test specification from another file.

Fixed

• auto output reference datasets are now recreated when the program
  is newer than the data files.

• Exotic hoisting bug (#1490).