MDict: Add volumes support for mdd files
MDict: minor parser refactor, fix inappropriate use of sptr
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.
Lupdate all translations
Update Russian translation
Updated Tajik Translation

Updated Tajik Translation
Merge pull request #313 from Ibragimov/master

Updated Tajik Translation
Disable the Scan Pop-up when a Preferences dialog is open
Fixed #314: Mac-specific: Do not enforce the default icon, allow icon customization.
Updated the Dutch localization (by Cris).
Updated French translation
Merge pull request #316 from virtualtam/master

Updated French translation
Update belarusian translation
Merge pull request #318 from quendimax/master

Update belarusian translation
XDXF: Fix infinite loop for malformed files. (Issue #319)
Mac-specific: Fix hotkeys when non-english keyboard layout selected
MDict: User friendly error reporting for article request
MDict: fix missing localizable string in 51ab9b0