preprarations
Test for conses
Remove bogus var used to detect api users.
transition to WrappedCons
Allow for specialized fixnum cons cells
Merge branch 'master' into issue7-specific-cons

* master:
  Travis: try pypy
  Travis: add-apt-repositoru non-interactive
  Travis: newer racket
  Add travis badge
  Travis: Install racket to use tests
  Travis: Install racket to use tests
  Enable travis-ci
Oh the syntaxe
typo
Fix cons jit test

Also: add filter, foldl, foldr to stdlib
change jit test
Merge pull request #7 from krono/issue7-specific-cons

Implement different representations for cons cells