Fix linkers errors with AllowSetForegroundWindow function
Backup/recover torrent persistent data into each individual .fastresume file. This should mitigate the problem of users losing their torrents' settings/savepath/label after qbt wasn't shutdown cleanly.
Optimize torrentperistentdata parameters and add utility funtions for previous commit.
Don't save resume data when torrent has an error. Prevents removing possibly useful .fastresume file and writing garbage.
Fix compilation with libtorrent 0.15.x.
Really fix compilation with 0.15.x.
Remove obsolete translation string (not used anywhere)
Improve loading of magnet metadata in the background.

Conflicts:
	src/qtlibtorrent/qbtsession.cpp
Merge pull request #955 from Gelmir/remove_obsolete_tr

Remove obsolete translation string (not used anywhere)
Merge pull request #942 from Gelmir/fix_fg_win_link

Fix linkers errors with AllowSetForegroundWindow function
Run lupdate.
Update Changelog.
Option to disallow bringing the torrent dialog to the front.
Run lupdate.
Fix magnet metadata loading. Update the queue and save_path correctly in all use cases.
Add Transifex client config.
Update translations for .desktop file.
Updated translations from Transifex.
New translation: Vietnamese.
Add the new translation to the build.