Add animation transition functions

[noartem]

Transition functions between two values (status: float [0...1], from: T, to: T) -> T

• Numbers 50 -> 100, 130 -> 68
• Points (0, 0) -> (10, 20), (100, 50) -> (200, 200)
• Rectangles {(10, 10), (20, 20)} -> {(30, 30), (40, 40)}
• Colors #ffaaaa -> #aaffff