Epub streaming

[aaronleopold]

Add support for streaming pieces of an epub to a client. This is already partially implemented in the Rust core.

Sump already supports very basic epub fetching and rendering (#34). It consumes the entire epub file, which is NOT ideal. I would like to be able to stream parts of the epub file as the user reads it, as opposed to downloading the entire thing to read it on the client. This will require a lot of research on epub file structure, as the core will likely have a lot of work required to support that kind of flow. Some work has already been started towards this.

Once there is a proof of concept for some sort of in house ebpub engine, I'll probably separate it into a standalone library that can be installed for both Rust and JavaScript/TypeScript projects (using likely https://github.com/getditto/safer_ffi).

References:

• https://github.com/getditto/safer_ffi -> for using Rust library in node
• https://readium.firebaseapp.com/?epub=epub_content%2Fpage-blanche&goto=epubcfi(/6/2!/4/2/2)

above link appears to: grab the container.xml, grab the package.opf, grab encryption.xml, grab nav.xhtml, grabs a page, like page 6, grabs epub styles

• https://www.iana.org/assignments/media-types/application/epub+zip