PDF rendering support

[bootkernel]

Not sure if it's out of scope but I would love to see viewing of PDFs supported as well. I think PDFium is a good option because it renders PDFs well and is permissively licensed.

[bluescan]

I'll leave this request open for a bit... but yeah, it's very likely out of the domain of this viewer. I'd expect functionality while viewing a pdf to include, for example, selecting and copying text -- not things tacent view would do well as it's primarily based on displaying buffers of pixel-data (textures) that have been pushed over to gpu memory.