Add deny -list. Rename permit to allow(list)

Filename mangling fix for when confusion between directory names and those in urls

Default root dir `~/` and allow permitting certain directories.

Configuration is passed to interpreters when making them. Also more docstrings and moving them to the top of the file. Will want metadata available without running the file.

minor

Untested Graphviz outputting files

Untested triggering on other files a notebook may depend on

Second type of stderr because PythonSubprocessInterpreter catches them in two ways

Add sequence of highlighters to use and provide `need_progs` to interpreters

Check `MainModuleDict` that also checks `need_progs`. Better combination of configs

The `ModuleDict` approach applied to the highlighters also

dot, hevea(latex) and discount(markdown) look if the binaries are there

Allow configuring what interpreters/wrappers to use and allows fallbacks too

`.info_done` not used. minor

More consistent output-file determining, `.load` function on state_json wrapper

Much neater i think. No more double treatment of files

Extract the whole per-file-name thing. Not sure if i am doing this right..

Wrapper that times how long the wrapped objects take to complete

Start and keep updating immediately. Needed to make the server threaded.. Surely potential trouble when accessing at the same time..

Fix saving, remove `.filename` from HTMLOutput info