CC-5709 / CC-5705 : Airtime Analyzer

* Finished the skeleton of the airtime_analyzer service.
* Basic round-robin, reliable AMQP messaging works.
* Using multiprocess arch so the daemon survives analyzer crashes and
  avoids failures propagating to other nodes.
* Basic metadata extractor using Mutagen is done.
* HTTP requests to the File API to are next to come...

python_apps/airtime_analyzer/airtime_analyzer/replaygain_analyzer.py

@@ -0,0 +1,12 @@
+from analyzer import Analyzer
+
+''' TODO: everything '''
+class ReplayGainAnalyzer(Analyzer):
+    
+    def __init__(self):
+        pass
+    
+    @staticmethod
+    def analyze(filename):
+        pass
+