Add daemon detached mode (--detached, -d) that runs agent in the background and returns immediately

trains_agent/interface/worker.py

@@ -72,6 +72,11 @@ DAEMON_ARGS = dict({
         'help': 'Do not use any network connects, assume everything is pre-installed',
         'action': 'store_true',
     },
+    '--detached': {
+        'help': 'Detached mode, run agent in the background',
+        'action': 'store_true',
+        'aliases': ['-d'],
+    },
 
 }, **WORKER_ARGS)