Add Metrics

* Fork server/bleed_serve for Moz specific changes
** Add metric tracking. This is statsd supporting as well as stores a local instance snapshot.
** Some work done to shore up arguments (default values, et. al.)

Notes:
I've tried to stick to the same model as the original code where possible. It might be useful to diff server/bleed_serve.go to see actual changes. 
The metric handler is an anonymous function in order to keep the code footprint smaller.
Kind of not a fan of docopt, mostly because of the way go doesn't handle interface dereferencing.