Start cscheme
scheme: make it into its own directory
scheme: first version of OCaml implementation

The scoping model is substantially different from that in the Python version, and I realized I don't particularly like either variant. I'll come up with a better model, probably involving nested symbol tables.
Merge branch 'master' of github.com:JelleZijlstra/lambda
ocaml scheme: don't print as much by default
scheme: more test files
scheme: start work on testing skeleton for all implementations. OCaml currently fails one of the two tests.
Add some more tests
Fix OCaml to support multiple statements in a lambda body
Also fix statement_list in Python
ocaml: fix wrong environment after function call