wpView:
- Don't wrap single-line URLs in [embed]. Use them directly in generating a view.
- If the embedding HTML contains a script, "sandbox" it in an iframe to prevent it from changing the editor DOM.
- Automatically add toolbar and overlay when needed.
- Try to embed single-line URLs only if they are pasted in an empty paragraph.
Props avryl, see #28195
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git-svn-id: http://core.svn.wordpress.org/trunk@28562 1a063a9b-81f0-0310-95a4-ce76da25c4cd