use KM.client() method in ConsoleApp
add QtKernelManager with restarter
KM.client creates a client with a shared Session
fix callbacks/_callbacks typo
front ends can have both Manager and Client
qtconsole autorestarts
expose restart callbacks via KernelManager
fire 'dead' callbacks when kernel dies before its first heartbeat
send status messages when kernel is auto restarted
handle new autorestart javascript-side