add lifecycle handler and call registered blocks after_server_bind when ...

...running, will fill in more lifecycle events as we continue to build up the server

in building out the zero-downtime strats it became noticeable that on rubies that have a significant boot time (looking at you Jruby) that we need to have a way to signal that the app has been bound to the rpc port and is available to serve requests and then the app should have the option of taking an action

added lifecycle events and specifically "after_server_bind" to fire a callback once it has been bound (we are touching a file to tell our deploy system to open the server for connects)