Translate the title for the User Manual
Amazon metadata download: Fix cover not being found for some books because of a website change at amazon.com
More amazon cover finding fixes
Metadata download: Prioritize results that have the same language as the current calibre user interface language

Also allow plugins to override how merging treats results without an
ISBN
Amazon metadata download: Do not prefer results with an ISBN, since Amazon now lists a large number of ISBN less titles
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Handle large common data being sent to workers (30MB+)
Fix updated strings in simple_index.rst not being marked for translation
Make set_common_data asynchronous
Re-organization
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Edit Book: Fix handling of XML unsafe characters (like <, > and &) inside <style> tags
More workarounds for bad translations of template function signatures
Fix various redirected/broken external links in the User Manual
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Eliminate deadlocks in the pool at the cost of a small chance to leak worker processes