qTox will automatically import the old history on startup.
This new database code is much more robust.
It is very resilient and will not corrupt or disappear after a crash or
power failure, unlike the old code.
The on-disk database format is also much more compact now.
The database sync option in the advanced settings has been removed,
we know run many database operations asynchronously so performance
should not be a problem anymore, but we always ensure resiliency
in case of abrupt termination, so there is no tradeoff anymore.
Someone was connecting a singal to a lambda capturing this, and never disconnecting it in the destructor. Capturing this is DANGEROUS, kids, don't do this at home.
In case a previous instance crashed, we were trying to activate the current owner before even checking if it was still alive, this resulted in qTox needing to be restarted twice after a crash.
This patch adds ability to override qTox window and tray icons with ones from user's desktop theme. Some people prefer keeping tray icons consistent to achieve best looks.
Following theme icons used:
* qtox: general window icon which is also used in taskbar
* qtox-online, qtox-offline, qtox-busy, qtox-away, qtox-invisible, qtox-event: tray icons
If theme icon is not available then default built-in icon will be used.