solves #153

Add master = true to uwsgi.ini

plugins/webui/uwsgi/uwsgi.ini

 module = plugins.webui.run
 chmod-socket = 666
 vacuum = true
-die-on-term = true #enable sigterm for killing
+die-on-term = true
+master = true

progs/slim/slim.py

             continue
         pid = pids[name]
         try:
-            os.kill(pid, signal.SIGINT)
+            os.kill(pid, signal.SIGTERM)
         except ProcessLookupError:
             logging.warning("The instance %s seems to be in error, no process \
 with pid %d found" % (name, pids[name]))