Can't change fps without making a timeline

[t-makaro]

I'm considering an API addition that allows:

anim = amp.Animation([block], fps=fps)

where fps gets passed to the constructor of Timeline when no timeline is passed.

Another option is to allow Timeline to accept an integer for t so one would do:

anim = amp.Animation([block], Timeline(len(block), fps=fps))

cc @TomNicholas Thoughts?

[TomNicholas]

Just seen this, I like the first option for an updated API.

I wonder if it perhaps makes more sense to think of the Timeline object as containing information about the slider, whereas fps would be a property of the Animation?