Remove dogstatsd-python in favor of dogapi

Also added datadog application to commom django apps and set it to use
a local statsd server by default.

common/djangoapps/datadog/startup.py

@@ -1,12 +1,25 @@
 from django.conf import settings
-from dogapi import dog_http_api, dog_stats_api
+
+from dogapi import dog_stats_api, dog_http_api
+
 
 def run():
     """
     Initialize connection to datadog during django startup.
 
-    Expects the datadog api key in the DATADOG_API settings key
+    Can be configured using a dictionary named DATADOG in the django
+    project settings.
+
     """
-    if hasattr(settings, 'DATADOG_API'):
-        dog_http_api.api_key = settings.DATADOG_API
-        dog_stats_api.start(api_key=settings.DATADOG_API, statsd=True)
+
+    # By default use the statsd agent
+    options = {'statsd': True}
+
+    if hasattr(settings, 'DATADOG'):
+        options.update(settings.DATADOG)
+
+    # Not all arguments are documented.
+    # Look at the source code for details.
+    dog_stats_api.start(**options)
+
+    dog_http_api.api_key = options.get('api_key')