Lots of changes, tweaks, updates.

- Added <noscript> tags around date and count of signatures for when no js.
- Added open graph tags.
- Added tweet/FB/email buttons (all static, no external js) to the post-signup page
- Prettied up the post-signup page.
- Added meta description tag.
- Fixed initial height of signatories container so it doesn't overflow.
- Moved gandi.net to companies.
- Added Public Knowledge to email rotation

NOTE: Make sure to upload all images and update urls before uploading. Make sure open graph image url is also updated.