Imio.helpers

-----------------

- Added `content.get_transitions` to be able to get available transition ids
(as `wfTool.getTransitionsFor` returns a list of dict with transition infos).
[gbastien]
- Added `adapters.MissingTerms`, a base `z3c.form` missing terms adapter to be
extended by local packages.
[gbastien]
- Added cache auto invalidation mecanism when using `cache.get_cachekey_volatile`
the caller method can be passed, it's name is stored in the volatiles registry
then when calling `cache.invalidate_cachekey_volatile_for` with
`invalidate_cache=True`, every cached methods are invalidated from `ram.cache`.
This will make stale cache be invalidated immediatelly as when a date changed,
the existing cache is never used again.
[gbastien]

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- Require `plone.api>1.9.1` because we need `content._parse_object_provides_query`.
This is necessay since we added `content.find`.
[gbastien]

-----------------

- Renamed `content.ur_find` to `content.find` with unrestricted parameter.
[sgeulette]
- Fixed `content.find` to avoid error if corresponding looped object is deleted.
[sgeulette]

-----------------

- Fixed `content.get_user_fullname` that was breaking when user had no fullname.
[gbastien]
- Added `content.ur_find` that's the same as api.content.find but unrestrictedly
[sgeulette]

-----------------

- Added `xhtml.replace_content` function that will replace the content of given
XHTML tag with some other content. This relies on package `cssselect` that is
added as an extra dependency thru `imio.helpers[lxml]`.
[gbastien]

-----------------

- Added `imio.helpers.SortedUsers`, a vocabulary listing users sorted using
`natsort.humansorted`. We need to rely on `natsort` to handle this.
[gbastien]
- Fixed bug in JS function `submitFormHelperOnsuccessDefault` called onsuccess
by `submitFormHelper` to only consider response as a file to return if
responser header `content-length` is found in request, this avoid returning
a wrong blob object when called code returns an error message.
[gbastien]