Add list value type
Remove Unit
Remove If, Def, Do, and Apply value variants

Lots of compile errors :(
Fix up various pattern matching constructs
Add vim temp files to .gitignore
Merge branch 'master' of https://github.com/bjz/rusp
Fix make check build

The tests still fail
Update description in README
Use test! macros to give correct line numbers for failing tests
Add James Miller to AUTHORS
Handle evaling (), fix tests
Merge pull request #3 from bjz/dev-bjz

Add list value type
Implement function calls, and use this to move builtins to the global environment

This includes adding macros (user-definable via `(macro (args*) body)`), and
quasiquotation.

Minor changes:

- Rusp::empty() creates a completely empty environment, Rusp::new() creates
  one with the default globals, and Rusp::new_with_otuer() creates an empty
  one with a parent scope.
- Some useful functions like `print`.
- Makefile and .gitignore adjustments
- The parser consistently returns Result<Value, ..> (rather than sometimes
  returning Result<~Value, ..>)
Usability improvements to the repl, don't print () or the AST.

Also, don't save empty lines.
Use @ everywhere to avoid cloning the AST
Parse multiple symbols from a source string.

i.e. don't ignore the "(b)" in "(a) (b)".
Fix tests after the parse change
Merge pull request #5 from huonw/eval-macros

Apply, macros, @ boxes, nicer repl
Separate macros into separate Value variants
Flatten list pattern matching