Adds a LODEL2LOGDIR to buildconf.py
Adds a nginx-conf option to slim
...

Now create an INSTANCE_NAME.sock in @localstatedir@/uwsgi_sockets
Note : the localstatedir is wrong -_- /usr/var instead of /var........

SLIM is now able to edit configuration from CLI, to start instances etc.

Deleted the json "db" of slim.py : progs/instances.json
Add features to SLIM :
- interface configuration editing from CLI
- better listing

solves #145

Now slim is able to create an instance, run make all, and start an interactive python without errors
refs #145

Able to :
- create/delete instances
- list instances
- run make %target% in all instances
- edit configuration given an instance name

refs #145