Refactor KittenServer signal handling
Fix signal handling for greenlets

Also refactor logging and reintroduce KittenServer.torn.
Refactor KittenServerTeardown tests
Add handling of KittenRequest responses
Change Server worker sleep to 0.1s
Refactor how Node.ping() works
Add Request.host property
Add context sensitive logging to Server
Add context aware socket binding in Server
Add 'message' as optional field for base schema
Add disabled Ping integration test