Formats: Add ability to annotate Word, Excel & Open Office docs (like Bookends tool)

[dwhly]

Question: Possibility that we might seek out additional format viewers that could render related document types directly in the browser.

Examples: https://github.com/khoaho/xls.js

[tilgovi]

I might suggest that we not try to "view everything as HTML and annotate that" if we're going to tackle even more formats. Instead, we might have to go to hosted solution and do more on the back end. In that case, Apache Tika is probably our tool. https://tika.apache.org/

[dwhly]

For reference apparently Florian Reuter, behind the project http://www.naverage.com/ is highly knowledgable about these areas and might be a good resource at the right time.

[tilgovi]

Clearing out old, stale feature requests. If this is something that's a definite focus for us let's make a placeholder repo with a little README for a hosted viewer.