Add Draft.js copy-paste handling overrides from draftjs-conductor. Fix #147

[thibaudcolas]

Fixes #147. Adds Draft.js copy-paste handling overrides from draftjs-conductor. This makes Draftail always preserve the full content as-is when copy-pasting between editors. See thibaudcolas/draftjs-conductor#2) and #147 for more info.

Also: Update to [email protected]. This does not include any functional changes, but will cause a duplicated dependency for projects having both draftail and draftjs-filters as deps if they don’t also update draftjs-filters.

[thi-bot]

	Warnings
⚠️	This pull request updates the library. Should the API reference be updated as well? The User guide?

Generated by 🚫 dangerJS

[thibaudcolas]

@thi-bot we're good. The user guide references #138, this will indeed need to be updated as part of the next release. A link to this issue should be added to Danger as well.

[thibaudcolas]

This PR does very little as most of the work was done in thibaudcolas/draftjs-conductor#2, so I'll merge now to facilitate testing via the demo site. We can still change the implementation as required in a separate PR.