Collective.editablemenu

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- Remove unused old code
[cekk]
- Fix menu render when there are no settings for the current folder
[cekk]
- Add initial test suite (functional and acceptance)
- Add test suite (functional and acceptance)
[cekk]

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- Added custom events when the menu is opened, closed and loaded
[pnicolli]

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- Fixed deprecated plone.directives.form import
[pnicolli]

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- Fix zcml condition for registering the global_sections viewlet. It was adding two different viewlets simultaneously on Plone 5, now one of those is gone.
[pnicolli]
- plone.protect js script was being added to the submenu html, now it's removed manually from the async response.
[pnicolli]
- Moved configuration format to using a json string
[daniele-andreotti]
- Completely new controlpanel layout
[pnicolli]
- Fix choose_site_menu_config method to take the right path
[fdelia]

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- Fix url generation for simple_link field. Now can handle correctly both
internal or external links.
[cekk]

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- Fix upgrade steps [lucabel]