Jupyter kernel for PARI/GP

[Jeroen Demeyer <jdemeyer@cage.ugent.be>]

Hello pari-dev,

I have made a first version of a Jupyter kernel for PARI/GP. Jupyter 
originally started as IPython, providing a command-line and a web-based 
notebook interface to Python. But now it expanded and it supports many 
programming languages.

My pari_jupyter project can therefore be used as web-based notebook 
interface for PARI/GP. The code is hosted at
https://github.com/jdemeyer/pari_jupyter
and you can download a tarball at
http://sage.ugent.be/www/jdemeyer/sage/pari_jupyter-1.0.0.tar.gz
SageMath users can also get it at
http://trac.sagemath.org/ticket/19372

It requires a git version of Cython and a git version of PARI. The 
latter is needed because of pari_sighandler() and gp_read_str_multiline().

Features:
* complete GP syntax thanks to gp_read_str_multiline()
* simple TAB-completion (it completes functions and members)
* shift-TAB shows short ?help tooltips
* interrupts work

Not done (yet):
* history
* long ??help
* breakloop
* syntax highlighting
* logo (do I have permission to use the official PARI/GP logo?)
* TAB-completion like in GP (hard since the GP TAB-completion is really 
hard-wired for readline)


Cheers,
Jeroen.