Elasticsearch-dsl

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Compatibility with Elasticsearch 2.x:

* Filters have been removed and additional queries have been added. Instead of
``F`` objects you can now use ``Q``.
* ``Search.filter`` is now just a shortcut to add queries in filter context
* support for pipeline aggregations added

Backwards incompatible changes:

* list of analysis objects and classes was removed, any string used as
tokenizer, char or token filter or analyzer will be treated as a builtin
* internal method ``Field.to_python`` has been renamed to ``deserialize`` and
an optional serialization mechanic for fields has been added.
* Custom response class is now set by ``response_class`` method instead of a
kwarg to ``Search.execute``

Other changes:

* ``FacetedSearch`` now supports pagination via slicing

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* ``Search`` can now be iterated over to get back hits
* ``Search`` now caches responses from Elasticsearch
* ``DateHistogramFacet`` now defaults to returning empty intervals
* ``Search`` no longer accepts positional parameters
* Experimental ``MultiSearch`` API
* added option to talk to ``_suggest`` endpoint (``execute_suggest``)

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* ``FacetedSearch`` now uses its own ``Facet`` class instead of built in
aggregations

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* added support for (index/search)_analyzer via 143, thanks wkiser!
* even keys accessed via ``['field']`` on ``AttrDict`` will be wrapped in
``Attr[Dict|List]`` for consistency
* Added a convenient option to specify a custom ``doc_class`` to wrap
inner/Nested documents
* ``blank`` option has been removed
* ``AttributeError`` is no longer raised when accessing an empty field.
* added ``required`` flag to fields and validation hooks to fields and
(sub)documents
* removed ``get`` method from ``AttrDict``. Use ``getattr(d, key, default)``
instead.
* added ``FacetedSearch`` for easy declarative faceted navigation

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* Metadata fields (such as id, parent, index, version etc) must be stored (and
retrieved) using the ``meta`` attribute (58) on both ``Result`` and
``DocType`` objects or using their underscored variants (``_id``,
``_parent`` etc)
* query on Search can now be directly assigned
* ``suggest`` method added to ``Search``
* ``Search.doc_type`` now accepts ``DocType`` subclasses directly
* ``Properties.property`` method renamed to ``field`` for consistency
* Date field now raises ``ValidationException`` on incorrect data