send ocaml reponses as pyout to get cell no's.

response messages coded as html so we can format them.

enable (for now) '-g' so we have stack back traces.
Redo code execution, in particular return messages

Code is executed phrase by phrase and return messages built up into
a list.  These are then individually formatted into html and
sent to ipython.

For html formatting compiler outputs are in gray and errors in
red.  Each output is limited to a css max-height, clicking on the
message will expand/collapse it.  This avoids the compiler messages
dominating the notebook output, especially for modules.
load .iocamlinit startup script

Same semantics as .ocamlinit.

Remove camlp4, package etc options and replace with the startup script.

Note; debugging the startup script is tricky as the user interface isn't
fully up when it's loaded.  Errors are written to the log file though so
you can check there.