Collective.compoundcriterion

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- Nothing changed yet.

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- Do not break in `negative-previous-index` when some filters does not have
values (so the `'v'` is not there in the query).
[gbastien]

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- Added `negative-previous-index` and `negative-personal-labels` default adapters.
Rely on `imio.helpers`. Removed dependency on `unittest2`.
[gbastien]

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- Add Transifex.net service integration to manage the translation process.
[macagua]
- Add Spanish translation
[macagua]

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- When getting the adapter, if context is not the Collection, try to get real context
following various cases. This is the case when using Collection
from plone.app.contenttypes.
[gbastien]
- Do not use a SelectionWidget to render the querystring widget as it does not
exist anymore for plone.app.contenttypes Collection.
Use the MultipleSelectionWidget. This way finally we may select several
filters to build the query.
[gbastien]
- When using 'not' in queries for ZCatalog 3, 'query' level must be replaced by 'not' in query dictionary.
[sgeulette]

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- Return clear message when a query format is not plone.app.querystring compliant.
[gbastien]