Imio.actionspanel

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- In `load_actions_panel JS function`, do not reload in case of error or the
page is reloaded ad vitam. Display an error message instead.
[gbastien]
- When using `string:` expressions, do not insert a blank space like
`string: `` or it is kept once rendered.
[gbastien]
- Manage `IGNORABLE_ACTIONS` the same way `ACCEPTABLE_ACTIONS` so we filter out
first every non relevant actions then we evaluate it.
Removed management of `IGNORABLE_CATEGORIES` and `IGNORABLE_PROVIDERS`, we
only keep `object_buttons` and providers `portal_actions/portal_types`.
[gbastien]

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- Fixed message `KeyError: 'confirm'` in Zope log when a transition is
triggered on an element for which it is not available anymore
(already triggered in another browser tab for example). In this case,
we just refresh the page.
[gbastien]
- Fix `saveHasActions` is not called when only untriggerable transitions.
[gbastien]

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- When showing actions and ACCEPTABLE_ACTIONS is defined, directly worked
with those restricted set. Faster method.
[sgeulette]
- Added parameter ActionsPanelViewlet.async (set to False by default) to be
able to render the actions panel viewlet asynchronously using a JS Ajax
request. Set every JS ajax request with async:false to be sure that screen
is refreshed when state changed.
[gbastien]
- Disabled showOwnDelete when 'delete' is in acceptable actions
[sgeulette]

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- Install `collective.fingerpointing` as we rely on it.
[gbastien]
- By default, do not render the viewlet in overlays.
[gbastien]

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- Use safely unicoded transition title.
[sgeulette]

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- Moved `views._redirectToViewableUrl` logic to `utils.findViewableURL` so it
can be used by external code.
[gbastien]
- Don't nullify margin of actionspanel-no-style-table.
[sgeulette]