Snapshot phantomjs rack application created
Shapshot: phantomjs PNG service takes WxH  params

relative images are re-written (usually?)

Here the background image isn't rendered: http://screencast.com/t/5offHW8nfP
But here it is: http://screencast.com/t/QRl6QWwszFu
Shapshot phantom: Save html, use base_href, &  CSS

Instead of rewriting the html and css, we simply change the doc base.
We are saving both HTML and PNG files now, so that we can debug the html

Shapshot application.js: extract snapshot.js send css, send base_url

I removed the snapshot specific code out of application.js and into its
own javascript file.

Also: We now send all the stylesheets in the page, and a base url.
snapshot: interactives.html: Snapshots go to extra's area.

Also include snapshot.js
snapshot.js: phantomjs : Canvases ➙ data-url png's
snapshot.js: phantomjs:  Works through iFrame too…
interactives.html.haml click snapshot label opens section.
snapshots: rename efforts to shutterbug. Place in lib/shutterbug
snapshot: Rack app also serves up the shutterbug.js
Snapshot shutterbug.js add background div behind canvas rendered pngs

Fixes snapshot fidelity issue where the canvas has a background attribute.