Need to split arguments manually because QProcess::startDetached(QString)
will strip off empty parameters.
E.g. `python.exe "1" "" "3"` will become `python.exe "1" "3"`.
Closes#8454.
Using iostream usually adds a lot of other operators (<<, endl), whereas
*printf takes only 1 function call.
Also use qUtf8Printable whenever possible.
Avoid temporary string allocations. They are only used to convert to
something else.
QString::xxxRef() returns a QStringRef. QStringRef avoids the memory
allocation and reference counting overhead of a standard QString by simply
referencing a part of the original string.
qDebug(), qInfo(), qWarning(), qCritical(), qFatal() expect %s arguments
to be UTF-8 encoded, while qPrintable() converts to local 8-bit encoding.
Therefore qUtf8Printable() should be used for logging strings instead of
qPrintable().
Arguments include adding torrents as paused/started, skiping hash check, setting category, downloading in sequential order, downloading first and last pieces first, and skipping the 'add new torrent' dialog. Added TriStateBoolOption class for specifying options that don't have a default value when unused (e.g. add-paused). Also improved command line usage text to include more information, have better organization, and not exceed 80 columns in width. Also also added firstLastPiecePriority field to BitTorrent::AddTorrentData, and modified TorrentHandle so that if first/last piece priority should be on, it will be toggled on after the torrent's metadata has loaded.
Commit dd0537d changed torrents startup code adding alerts processing
into it. Therefore alerts were processed before UI code subscribed to
signals and therefore part of alerts was not reflected in the UI.
Thus here we do not start torrents in Session constructor, but do that
from Application::exec() after UI was constructed and is ready to process
signals.
Vladimir Golovnev (Glassez)