sync with Kovid's branch
update fronda.recipe
Update fronda
Fix #1130478 (Chrome incompatibility)
Add tests for covers
Add tests for formats
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Implement getting of covers and add tests for it
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Add API to get formats
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When tweaking/polishing an azw3 file that does not have an identified content ToC, do not auto-generate one. Fixes #1130729 (azw3 files tweak will duplicate table of contents after rebuild)