JKind v1.5.1

Features

• Added enumeration types, for example

type state = enum { A, B, C, Error };

• Added Turing machine example.
• Users of the JKind API may now pass null to AST constructors
  in place of empty lists.
• Added -xml_to_stdout flag which prints results as an xml file
  directly to the standard output.
• Allow types and constants to reference previous types and constants
  rather than requring declaration before use.

Changes

• We no longer support equations with no left-hand side. Instead, one
  must at least use () as the left-hand side when an equation assigns
  no variables.
• Constants and enumeration literals must have globally unique names
  (e.g. cannot conflict with node variables).

Fixes

• Added support for 'unknown' result from Z3.
• Improved parsing performance.
• Fixed bug in tuple handling.
• Fixed unguarded pre check with respect to node calls.
• Fixed integer overflow error with bounds checking for arrays.