Animation PlayMode and Duration were reset each time Play/Pause buttons were clicked.
This prevented using general paraview animations by manually chosing animation settings.

Now, the animation PlayMode and Duration is directly updated when the user selects a different playing speed,
and Play/Pause buttons have trivial behavior of invoking Play/Pause commands.
The animation Duration is also updated when timesteps range changes, e.g. when a new pcap is loaded.

NOTE : When upgrading LVCore in your specific LidarView based application,
you should consider removing the line `app.scene.UpdateAnimationUsingDataTimeSteps()`
in function `applogic.openPCAP()`. Without this change, the speed mode will be set to 'All Frames'
when a new pcap will be loaded. By removing this line, the speed mode and animation settings
won't be changed, and will be kept as user set them before.