Avoid extra pre-auth api requests

Close #1586
Always copy bootstrap and destroy in extension
Add PDF.js assets to the Chrome extension

This comes from PDF.js v1.0.473, generic build, with zero modification.
Insert H code into the PDF.js viewer html
Fix URI and metadata handling for PDF documents

Don't load the Document plugin for PDF files; Annotator's PDF plugin
provides the fuctionality (uri+metadata extraction) in these cases.
When displaying annotations, avoid non-clickable URIs
Modify background.js for PDF.js

inject and remove logic has been modified to handle
PDF.js differently.
Update Chrome extension manifest.json

Remove a bunch of useless permissions,
update a few filenames
Updated PDF plugin to f278e278 (pdf-update branch)

Also update guest.coffee to use async metadata extraction for PDF