Updated French translation
Merge pull request #306 from virtualtam/master

Updated French translation
Update Tajik Translation

Tajik Translation Updated
Merge pull request #308 from Ibragimov/master

Update Tajik Translation
Aard: fix outstanding elements (issue #309)
Add jpg image format as an option for dictionary icons.
audio: give more meaningful error message for ao_open_live(). see #312
audio: localizable error string
Add "Copy as text" feature (issue #311)
Lupdate all translations, update Russian translation
Added an option to hide GoldenDict identification in the HTTP User-Agent headers (Issue #259).

A new preference in the "Network" tab is added:
* Do not identify GoldenDict in HTTP headers.