News in 3.29.2, 2018-05-21
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* A new, more flexible book management architecture in the libdevhelp:

 - DhBookManager is now completely empty and entirely deprecated, the minimum
   amount of API is kept to not break Anjuta. It has been replaced by a more
   flexible infrastructure: DhProfile, DhSettings and DhBookList. If an
   application uses only the default libdevhelp widgets it will still work fine
   – even if the code of the application is not adapted – because in that case
   it will use the default DhProfile, which contains the same content as how
   DhBookManager was implemented.

 - Whether a DhBook is enabled/selected is now decoupled from DhBook:
   dh_book_get_enabled() and dh_book_set_enabled() have been removed, as well
   as the DhBook::enabled and DhBook::disabled signals. For a book to be
   enabled it now needs to be part of a DhBookList, which is more flexible
   because there can be several different DhBookLists in parallel.

 - Allow custom search paths to load DhBooks, with DhBookListDirectory.

* Port other Devhelp classes to DhProfile and DhBookList.
* Listen to external changes to the "books-disabled" GSettings key.
* Some code cleanup and minor bug fixes.
* Flatpak: convert manifest to YAML.
* Translation updates.