Updated to new version of PDF.js library.

This new version should:
- not crash on current Chrome version, see
  https://github.com/mozilla/pdf.js/issues/4104
  https://code.google.com/p/chromium/issues/detail?id=333594
- provide better position of text segments, see
  https://github.com/mozilla/pdf.js/pull/4089
esprima errors when upgrading PDF.js should not happen anymore.

See:
https://github.com/mozilla/pdf.js/issues/4175
https://github.com/mozilla/pdf.js/pull/4180
Document why mrt command occasionally disappears.
Updated PDF.js again.
Updated code to new PDF.js version.
Cleanup annotator so that we can open more than one publication.
Log PDF.js settings on errors.
Merge branch 'new-annotations3' into new-annotations3-highlight