Binary upgrade, fixes #85

This PR contains couple of features:

* Simple support for live binary upgrades
* Remove misleading connwatcher that does not work properly
* Track connections to sockets and emit stats 
Can you separate the std lib packages?

    import (
    	"net"
    	"net/http"
    	"sync"

    	"github.com/mailgun/vulcand/Godeps/_workspace/src/github.com/mailgun/metrics"
	)