ivory-quickcheck requires QuickCheck >= 2.7 for Test.QuickCheck.Random

Current Haskell Platform includes QuickCheck 2.6 which isn't sufficient.
Added the formal model and proofs of type safety
Add twosComplementCast to Ivory.Language.
Added document generation scripts, cleaned up output a little
Added pdf for isabelle theories
ivory: export fromTypeNat primitive
concrete syntax: proc args are idents, not tyidents.
ivory-examples: better pub/priv example.
concrete syntax: added type synonyms and top-level expr. declarations.
parser: allow zero or more stmts rather than 1 or more.
wibbles: remove warnings.
concrete syntax: allow empty procedure bodies.
concrete syntax: includes (module depends).
concrete syntax: change &> to . for field access. What was I thinking?
examples: remove deprecated file (see file.ivory for concrete examples).
concrete syntax: c-like types in struct defs.
concrete syntax: builtin functions syntax, add cast functions.
concrete syntax: bug (unary op is binary op).
ivory lang: add twosComplementRep to cast from signed to unsigned
representation.
concrete syntax: add twosComplementRep (signed to unsigned).