refractor: simplify torrent model signal emissions
The Torrent->Application signal connections make up for about 5% of the
app's memory use. Move this to the TorrentModel so that there are only a
handful of signal connections.
Moving signals to TorrentModel means batch change signals can be emitted
instead of per-change-per-torrent emissions and can be handled that way.
* refactor: keep torrent's time properties as time_t
Comparing QDateTimes is expensive. Keep the torrents' time properties in
the time_t form that we got them from RPG in; difftime() is cheaper.
This way all the qualifiers (`const`, `volatile`, `mutable`) are grouped
together, e.g. `T const* const x` vs. `const T* const x`. Also helps reading
types right-to-left, e.g. "constant pointer to constant T" vs. "constant
pointer to T which is constant".
There're places where manual intervention is still required as uncrustify
is not ideal (unfortunately), but at least one may rely on it to do the
right thing most of the time (e.g. when sending in a patch).
The style itself is quite different from what we had before but making it
uniform across all the codebase is the key. I also hope that it'll make the
code more readable (YMMV) and less sensitive to further changes.
We don't currently (if ever) provide context help, so the button is
useless. Moreover, on Windows 10 it's even larger than before and
sometimes title text doesn't fit because of it.
Simplify DND checkboxes drawing, this also fixes incorrect drawing on
Mac when file tree widget is inactive.
Do better job calculating column widths for file tree to avoid ellipsis.
Fix file tree sorting order for size and priority columns.
Change key to toggle priorities to Shift+Space instead of Enter/Return
to avoid conflicts with name editing and default button handling.
Fix selected tracker item background drawing in certain cases.
Split FileTree.{h,cc} and FilterBar.{h,cc} files so that each class
is in its own file.
This breaks translations (some classes got renamed => context changed),
to be fixed by next commit (along with Tx sync).
