Correct qTox.desktop

With an additional ';' installing qTox desktop file resulted in warning:

/usr/share/applications/qTox.desktop: error: value "InstantMessaging;;AudioVideo;Network;" for key "Categories" in group "Desktop Entry" contains an unregistered value ""; values extending the format should start with "X-"
Windows installer: Fix Tox URI handling
Merge branch 'pr667'
Merge branch 'pr669'
Build .qm files in qmake, before RCC runs

Otherwise the resource compiler complains that it can't find our translations

Fixes #668
Fix #670
Fix #671
Remove dead assignement, useless include
Fix #674
Fix #673
Autoload last week of history on startup

Only if keeping history is enabled, of course
Don't free actions owned by the system tray menu

Thanks to mannol for reporting the issue
Update french translation
Add boolean 'sent_ok' to new history DBs

We can remember which message we couldn't send and build faux-offline messaging on top of that later
Show the date for each new day when loading history
Use Fusion by default if available

Only on first run, if you explicitely choose no style or another style, we don't change that. Fallback to no style if fusion isn't available.
Highlight on main buttons hover, fixes #295
Don't notify the same status change twice

Fixes #676
93a4d30 (Add boolean 'sent_ok' to new history DBs) fix: default value
Merge branch 'pr678'