Save torrents queue in separate file

[glassez]

See #9556 for explanation.

1. It saves/restores queue when "queuing" is enabled (unlike existing code). Is it acceptable change?
2. When user disables "queuing" it just stops saving queue file. Should it remove/clear queue file?

[Chocobo1]

When user disables "queuing" it just stops saving queue file. Should it remove/clear queue file?

I think yes, for the sake of more consistent program state when doing debugging.

[sledgehammer999]

I am done. I of course approve this. I'll test build it now. I'll comment again only if something's wrong with the test.

[sledgehammer999]

Should this feature be backported to v4.1.x series?
(assuming that libtorrent 1.2.0 final won't be released soon)

[glassez]

Should this feature be backported to v4.1.x series?

I targeting it to v4.1.5 and scheduling removal of deprecated code to v4.2

[sledgehammer999]

I targeting it to v4.1.5 and scheduling removal of deprecated code to v4.2

Depending on how many releases 4.1.x still has, the deprecation might be a bit too soon. I would target 4.2.2 or 4.2.3 for removal.

[glassez]

I would target 4.2.2 or 4.2.3 for removal.

Ok. No problem.
But I'm not sure we reach v4.2 soon (if it's sticks to libtorrent-1.2).

[glassez]

All conversations are resolved so waiting for final review.