Use white backdrop when possible.
Add back mozOpaque.
Remove mozOpaque for driver.
Update Swedish locale with 'printing_not_ready' string
Fixes PDF application switch in Firefox.
Update zh-TW locale for printing not ready message
Squashed commits to Polish viewer.properties.
(Removed English leftovers)
Updating Dutch translation with print warning
Merge pull request #3010 from piotrex/patch-2

Update Polish viewer.properties (translated "printing_not_ready")
Merge pull request #3011 from Snuffleupagus/printing-not-ready

Update Swedish locale with 'printing_not_ready' string
Merge pull request #3013 from xavier114fch/zh-TW

Update zh-TW locale for printing not ready message
Merge pull request #3014 from timvandermeij/print-warning-dutch

Updating Dutch translation with print warning
Updated Japanese locale
Merge pull request #3012 from yurydelendik/pdfjs-switch

Fixes PDF application switch in Firefox.
Update viewer.properties
Merge pull request #3009 from brendandahl/backdrop

Use white backdrop when possible.
Merge pull request #3015 from Haebaru/master

Updated Japanese locale