latest js_of_ocaml + topfind + webserver interaction

Latest js_of_ocaml almost removes all my hacks to the runtime.

Integrates filesystem with the webserver.

Implements topfind functionality.

Rejigged the makefile esp. invert expunge to list modules to
keep which simplifies things an awful lot.

Targets are all (minimum js toplevel) for full (jsoo+lwt+syntax).

Known bug with minimum version - camlp4 loads but extensions dont
work.  Also, unable to access Iocaml module and js_of_ocaml at
the same time.