share code between zmq channel handlers
add stdin channel to NotebookApp
specify socket identity from kernel.js

required for stdin routing
add stdin to notebook

dumb / gross / ugly jQuery modal dialog for now,
but it works!
flush stale messages on stdin channel prior to raw_input
use inline raw_input instead of a dialog
cleanup stdin event submission

follow example in rename notebook: remove form, bind keydown for enter,
avoiding shift-enter submitting the cell again.
tweak raw-input styling

should fix alignment of raw_input and prompt
add no-op on_message for iopub
fix color in raw_input
tweak raw_input style

more crowded, less jumpy
clarify first ws message names / messages
js comment about session id in first message
Merge pull request #3089 from minrk/stdin

add stdin to the notebook