Collective.embeddedpage

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- Added i18n translation files for EN, ES, CA.
[robdayz]

- Add serializer for Volto support.
[rodfersou]

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- Plone 5.2/Python 3 compatibility.
[timo,rodfersou]

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- Don't raise an exception when target page is empty.
[rodfersou]

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- Change development status to Production/Stabel in setup.py.
[timo]

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- Change header forwarding: Only forward http x-* headers and convert
zopes header names (e.g. HTTP_X_FORWARD_FOR to x-forward-for)
[csenger]

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- Dont double decode XML HTML pages.
[rofersou]

- Pass headers forward from original request.
[rodfersou]

- Make URL field not required.
[rodfersou]