Resizable tracks

[allejok96]

• Fixes bug where new instruments would not have LCD hidden in compact mode.
• Fixes bug where mouse cursor gets stuck in resize mode between track controls.
• Move common code in SongEditor and PatternEditor to TrackContainerView.
• Restore track head size on project reload.
• Resize track head in Pattern Editor when the windows is resized bigger again.
• Allow resizing tracks in the track content area.

One problem is that the new ResizeTrackLine doesn't propagate selection/right click though to the widget below. Possible solutions: don't draw the resize line over the TrackContentWidget. Or hack up something like:

ResizeTrackLine::mousePressEvent(QMouseEvent* event)
{
    QMouseEvent newEvent(event->type(), newRelativePos, ...);
    QApplication::sendEvent(trackContentWidget, &newEvent);
}

[regulus79]

I notice this PR seems to do a bit more refactoring than what is directly related to resizing the tracks. But I do like how much cleaner everything is, thanks!

[regulus79]

Would doing me->ignore(); return; work?

[allejok96]

I tested it and it doesn't work. I don't think mouse press events can propagate to the parent, but even if they did it wouldn't work because TrackContentWidget is a nephew to TrackResizeLine.