Tests for binders with multiple arguments.

These are expected to fail for now.
Fix #15 Parse binders with multiple arguments
Fixed a bug that causes type-checking arithmetic expressions to loop
Merge pull request #46 from plmday/master

Fix #45.
Improved debug information
Merge pull request #47 from plmday/master

Reword debug information for type checking.

See discussion in #45.
Add examples about basic arithmetics (see #21).
Systematically renamed `Nat' to `Int' and `nat' to `int' (fix #49)
Clean up multiple argument binders implementation.
Merge pull request #52 from morphling/mult-args-binders

Parse binders with multiple arguments
Merge pull request #51 from plmday/master

Rename Nat to Int.

The built-in type Nat always supported negative values,
so the clarify things, it is better to call it Int.
Format comment for haddock.

Try `cabal haddock` to see the difference.
Export function to show assertions.

This is necessary to name test cases for #48.
Implement monad transformers for computations with embedded assertions.
Run source files with assertions as unit tests (fix #48).
Merge pull request #54 from Toxaris/topic/assertions-as-tests

Run assertions as tests
Reorganize module hierarchy PTS.Syntax.*.

The new module PTS.Syntax exports everything the other modules of the
system need to know about the syntactic structure of PTS programs,
including the AST datatypes and support for folding, parsing, pretty
printing and substitution. These features are implemented in the
modules of the PTS.Syntax.* hierarchy. Fixes #34.
Split PTS.Syntax.AST.
Format list of exposed modules.

The list is now ordered alphabetically. List items are no longer
separated by commas to reduce diff noise when adding at the end
of the list.
Reorganize module hierarchy PTS.Dynamics.*.

The new module PTS.Dynamics exports everything the other modules of the
system need to know about the dynamic semantics of PTS programs,
including the Value type and support for evaluation, reification,
Normalization and  comparision of values. These features are implemented
in the modules of the PTS.Dynamics.* hierarchy.