Sphinx-needs

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* Bugfix: Links to parts of needs (:ref:`need_part`) are now stored and presented as *links incoming* of target link.

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* Improvement: Added dynamic function :ref:`check_linked_values`.
* Improvement: Added dynamic function :ref:`calc_sum`.
* Improvement: Added role :ref:`need_count`, which shows the amount of found needs for a given filter-string.
* Bugfix: Links to :ref:`need_part` in :ref:`needflow` are now shown correctly as extra line between
need_parts containing needs.
* Bugfix: Links to :ref:`need_part` in :ref:`needtable` are now shown and linked correctly in tables.

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* Improvement: :ref:`dynamic_functions` are now available to support calculation of need values.
* Improvement: :ref:`needs_functions` can be used to register and use own dynamic functions.
* Improvement: Added :ref:`needs_global_options` to set need values globally for all needs.
* Improvement: Added :ref:`!needs_hide_options` to hide specific options of all needs.
* Bugfix: Removed needs are now deleted from existing needs.json (:issue:`68`)
* Removed: :ref:`!needs_template` and :ref:`!needs_template_collapse` are no longer supported.

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* Bugfix: Fix for changes made in 0.2.5.

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* Bugfix: Fixed performance issue (:issue:`63`)

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* Improvement: Titles can now be made optional. See :ref:`needs_title_optional`. (:issue:`49`)
* Improvement: Titles be auto-generated from the first sentence of a requirement. See :ref:`needs_title_from_content` and :ref:`title_from_content`. (:issue:`49`)
* Improvement: Titles can have a maximum length. See :ref:`needs_max_title_length`. (:issue:`49`)