Update the torrentview when torrent status changes

[sadrul]

If 'Downloading' is selected from the sidebar, and a torrent from the torrentview is paused (either from the gtkui itself, or from another ui), then the torrent remains in the view, although it doesn't match the selected filter. The attached patch fixes the issue (I have added inline comments explaining the changes made).

[sadrul]

The attached alternate patch marks specific torrents 'dirty' when its status is changed. In the next update, the torrents marked dirty are updated (and unmarked 'dirty'), irrespective of whether it is currently being displayed in the torrentview. This solution also works, with the exception of being less noisy to the server than with the first patch.

As was suggested in IRC, the 'torrent_state_changed' signal could also be used. But, as was later discovered, the signal is not emitted when a torrent is paused/resumed, because of how torrent-states are currently used in libtorrent. So this signal, in its current state, can't really be used to fix this issue.

(This is all for reference ... I have a bad memory ;) )

[sadrul]

alternate patch (mark dirty, less noisy)

[andar]

Committed [3388]. Thanks!