Embed a Smash Notes episode or note

Add /embed to an episode or note address. That page is a player other sites can put in an iframe.

An episode at /p/show/e/episode becomes /p/show/e/episode/embed. Add /preview after that to copy the iframe code.

A note at /p/show/e/episode/s/note becomes /p/show/e/episode/s/note/embed.