entity_embed 8.x-1.0-alpha2

Entity embed 8.x-1.0-alpha2
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- #2593379 by Wim Leers, Denchev, slashrsm, Dave Reid: Fix handling of bubbleable metadata.
- #2656062 by webflo, Denchev, JamesK, marcoscano: Make hiding of Next button during Selection more robust.
- #2712111 by paranojik, slashrsm, Dave Reid, Wim Leers: Fix Embed specific attributes are cached along with the entity.
- #2706051 by slashrsm, Dave Reid, Wim Leers, Denchev: Require UUIDs for embedding with the dialog (remove data-entity-id from embeds)
- #2554687 by slashrsm, pixelmord, CTaPByK, Dave Reid, Wim Leers, Reinmar, Denchev: tag not being automatically added when an Entity Embed button is added to active editor toolbar
- #2706059 by Dave Reid: Filter out empty attributes.
- #2705611 by Dave Reid: Fixed no need to use jQuery in init().
- #2645458 by kmoll, slashrsm, smaz, rikki_iki, mariagwyn, asrob: Fix data-align and data-caption handling for image_formatter template.
- #2712107 by slashrsm: README is missing data-embed-button