Less copying in the JPX coder, merged and rebased
Prevent the annotationLayer to be recreated when the page is redrawn

This allows interactive annotations to keep their states after a resize
Merge pull request #4552 from dferer/annotations-refresh

Prevent the annotationLayer from being recreated when the page is redrawn
Merge pull request #4538 from fkaelberer/lessCopyingInJPX

Less copying in the JPX decoder
Preliminary attachments support

Added a partial Filespec support
Added getAttachments in API
Added a new attachments view in UI (with a new icon by @shorlander)