Move to YAML config and allow split functions

1. Move to a YAML-based configuration format instead of the original
   INI-based configuration to facilitate better organization and
   readability.
2. Modify the daemon to be able to operate in several modes based
   on configuration flags. Either networking or storage functions
   can be disabled using the configuration, allowing the PVC system
   to be used only for hypervisor management if required.

node-daemon/pvcd/log.py

@@ -45,6 +45,8 @@ class Logger(object):
             # We open the logfile for the duration of our session, but have a hup function
             self.writer = open(self.logfile, 'a', buffering=1)
             self.last_colour = self.fmt_cyan
+        else:
+            self.last_colour = ""
     
     # Provide a hup function to close and reopen the writer
     def hup(self):