Allow to remove all database prefixed by MONGODB_DB_PREFIX (in the conf of mass_deploy script)

using --plugin option instead of uwsgi_python3 shortcut (can be uwsgi_python34 etc)

Now we can run tests from the tarball generated by make dist

Allow generating a tarball that can compile and run lodel2 + deletion of unwanted Makefile.in files

Forgotten file was the PID list file
The bugfix concerns the conf when selection mongodb as datasource (quick & dirty solution : keep dummmy_datasource loaded so we don't have to modify the original datasource conf)

https://docs.mongodb.com/v2.4/reference/user-privileges/
https://docs.mongodb.com/v2.4/reference/privilege-documents/

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........

It a real buildtime variable, the localestatedir

Bufixes in start & stop functions
Add a -f --foreground option allowing to run an instance in foreground
There is one problem left : the unix socket creation is not done in the instance directory...

Using execl instead of fork to preserv the pid

Bugfixe in start
implements stop
add info in instance details

On configuration setter

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

when a value is composed only with space tabs etc consider it as None

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

- Written a new custom_list validator, it takes another validator name as argument (in order to validate items of list)
- Using it to validate list of plugins names

Allows runtest to run again =)

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

refs #145

Nescessary for refs #145