mainwindow: Show a title when the startup wizard is visible
elements: Avoid setting negative widths
timeline: Get rid of some clip animations
mainwindow: Remove a vbox element which is not useful
mainwindow: Consistent imports and move dead code around
clipproperties: Fix effect configuration UI destruction

The second resetKeyframeToggleButtons call was raising an exception.
medialibrary: Fix asset removal

    if paths is None or paths < 1:
TypeError: unorderable types: list() < int()