Copy deprecated d3.first into babelweb.js

To be removed in d3 v3.
Update d3js, switch to non-minified for dev
Upgrade to socket.io 0.9, disable priviledge dropping

No need to be root anymore to enable flash policy server
(port 10843 by default now).
Upgrade d3 to v3.1.5
Rewrite server-side in a modular way
Rewrite client-side in a modular way
Bump dependencies (node, connect, ronn)
Use socket.io automatic json encoding
Fix whitespaces in client
CSS highlight of current row
Remove js transitions

Use CSS transition for background color.
Do not use transition for changing text anymore.
Interpolate colors in HCL space
Ignore 'done' token
Ignore spurious 'change' events
Store multiple nodes on client