Add an output format option in playback settings. The options are
Detect, S16LE, and F32LE. Selecting Detect will use the existing
behavior and detect the native format when the pipeline starts. The
other options will set the format when the pipeline is built.
QTimeLine duration must be greater than 0. If set to 0, a default of 1000ms will
be used. To avoid this, enforce a minimum of 1ms for pause and cross fade values
if those fades are enabled.
This change provides the ability to set a fixed pipeline sample rate as an alternate to automatically negotiating it.
This can be useful on systems with sound cards that work at a fixed rate, as well as it can triage issues (on Windows)
where changing tracks hangs due to a problem with gstreamer's caps negotiation.