README: added instructions to build the toplevel
README: added instructions to build the toplevel

Ignore-this: 3e76f27bee8756b415206db07d3b52c3

darcs-hash:20110404113942-c8b6b-e6b551e7e61972d3f94ee707859ae1960c8aeb72

OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml