Creating new files to handle IPC stuffs : include/ipc.h src/ipc.c

Now logging a python traceback

The responder_loop handle better child creation & deletion. A conf struct
member indicates the number of seconds the pool have to be idle before deleting
a worker.
In a same way, the pool has to be busy for at least 1s before a new
process can be added (the -f flag indicate if the counter has to be reseted
when a new process is created, allowing spawn burst).
The spawn() function call sigaction 2 times for SIGINT & SIGTERM in order
to catch both.

And better handling of entrypoint import failure...

Bugfix consist of replacing the magic wrapper instance of os.environ (
aitomatically call os.putenv) by a normal dict instance.