Adding requirements for node.js

- Fixes #407
Merge pull request #457 from rackerlabs/gh-407

Adding requirements for node.js
Added Google Analytics and Core Metrics from old site

Copied code verbatim from

https://github.com/rackerlabs/devsite/blob/master/source/index.html#L1106-1130
Adding back Code of Conduct URL field.
Merge pull request #463 from ycombinator/code-of-conduct

Adding back Code of Conduct URL field
Adding sign-up button to header

- Fixes #464
Merge pull request #467 from rackerlabs/gh-464

Adding sign-up button to header
Merge branch 'dev' of github.com:rackerlabs/developer.rackspace.com into copywrite
Merge branch 'dev' of github.com:rackerlabs/developer.rackspace.com into copywrite
Merge branch 'copywrite' of https://github.com/annegentle/developer.rackspace.com into copywrite