Update Japanese language file

Update Japanese language file
Merge pull request #724 from sys9kdr/master

Update Japanese language file
Serbian translation updates
Fixed crash on choosing non-writable download location.
[FTP] Caching file icons, also added ftp to installer script and associationManager()
Portuguese update
Make "Switch to tab" translatable.

LocationCompleterDelegate does not include Q_OBJECT

Closes #725
Merge pull request #727 from smarquespt/master

Portuguese translation update
Merge pull request #726 from srazi/master

Fixed downloader issue and some ftp related changes.
Fixed building on both Linux & Windows.
[win] Don't check for default browser on startup.

Also cleanup in #ifdefs in RegisterQappAssociation
[win] Fixed building after last commit.
Serbian translation update/fix