Integrate array of paths returned by Xapian full-text search into the standard title search results

[Jaifroid]

This is a sub-issue of #769. Once Xapian search has been launched, we will need to deal with the returned array of paths. Currently, the implemented search in the JS port of libzim only returns paths of articles that contain the searched terms, not snippets or article titles. We already have an algorithm to take the paths, read the Directory Entries, and extract the article titles (which are not always the same as the article path). However, it may be faster to get the titles from the libzim port rather than process the paths the old-fashioned way, if we can expose a way to do that.

This issue should include integrating the search results into the list of articles already found by title search, which should include elimination of duplicates and prioritization. Search results with the searched term in the article title should be prioritized over full-text search that doesn't have the term in the title.

[Jaifroid]

Fixed in #935