Add rotate animation

[tbaranes]

No description provided.

[JakeLin]

Cool @tbaranes I am thinking repeatCount can have Infinite or have .RotateForever in enum. That would be useful for lots of cases. But don't know to how support Infinite in @IBInspectable property.

[lexrus]

How about let Infinite = -1?

[tbaranes]

I though about this, but I conclude that the user will set infinite as the repeatCount. @lexrus suggestion is a bit hidden (if you don't now, hard to find), but maybe the nicest one solution?

[JakeLin]

Float does have Float.infinity, that's why I chose Float for repeatCount instead of Int. And repeatCount should be Int realistically. We can use Float.infinity in code. but can't do it in Interface Builder. I think let Infinite = -1 is not a bad idea for IB because we never have negative repeatCount.

On the other hand, I found out the documentation is also important for IBAnimatable project, if we have let Infinite = -1, we need to update the API document to describe this workaround.

[JakeLin]

The reason why I said documentation is also important because Interface Builder doesn't support validation for the value and the range. When I observed the others used IBAnimatable and the API document can help out the supported options and value range.