Include .odt conversion to .html
See https://gist.github.com/ywarnier/8377800 (works fine).
This would enable the odt to html conversion without LibreOffice. It doesn't allow conversion from Impress docs though, but it's a nice little feature to add to the documents tool, maybe? (upload a document, then if it's an .odt, offer conversion to HTML so it can later be included in a learning path...)
It requires (as it is) the creation of an "images" directory to create the images from the document, but that has to be modified.
It's under LGPLv3, so we can include it.