metrics for routed and unrouted signals
do not register metrics if metrics subsystem is not enabled
fixed #404
optimization in sendnl routing
added 'uwsgi' transformation
transformation_template has been moved to a plugin
added no_content_length to the cache router
added better random initialization and rr/rand hash algos
implemented #284
busy_workers and idle_workers must be GAUGE
use uwsgi.start_tv for srand instead of recomputing it
completed metric threshold subystem
do not destroy the stats pusher loop on EINTR
added stats pusher default plugins
metrics as objects in stats subsystem
Support HTTP Status 509

Whilst this isn't an official RFC, it's documented on e.g. Wikipedia. http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_Server_Error
Merge pull request #447 from flavour/master

Support HTTP Status 509
added metric api to ruby
prepare for uWSGI 1.9.19
fixed template plugin