refs https://github.com/TryGhost/Team/issues/459
- re-use bookmark card styling
- approximate the data grabbed by metascraper (used when generating bookmark card contents) based on saved post data
refs https://github.com/TryGhost/Team/issues/459
- the SERP description was not falling back to the server-side generated `excerpt` field on the post
- removed outdated dynamic description generation from markdown card, should be replaced with dynamic description generation from mobiledoc if needed
refs https://github.com/TryGhost/Team/issues/459
- fixed incorrect tracked variable name for the email preview address
- fixed incorrect access of `this.post` instead of `this.args.post`
- re-throw any error that is encountered so the cause is not silently lost
refs https://github.com/TryGhost/Team/issues/451
- Added mobile view to the post preview modal
- Replaced tabs text with icons
- Moved back button and added publish button
- Changed copy-link design to be aligned with link preview in portal
- Changed layout for social previews
- Added images to the Twittr and Facebook previews
- Added labels to the social previews
- Changed styling for the "Preview post" button in editor
refs https://github.com/TryGhost/Team/issues/451
- disabled email tab when previewing a page (pages can't be emailed)
- added share preview url footer to browser tab
- added send preview footer to email tab
- added first pass at social tab contents
refs https://github.com/TryGhost/Team/issues/451
Start of new post preview prototype.
- adds preview button next to publish button
- opens new combined preview modal with desktop/email/social tabs
- desktop preview shows front-end preview url in iframe
- email preview fetches preview data as per the older email preview modal
- social preview to come later
