Fix LED animation code.
Update STM32 Timer example with animations.
Remove DummyLed class.
Generalize LED fading code into LinearAnimation class.

This template class uses fixed-point arithmetic for 8bit and 16bit integer types for fast calculations.
All other types default to floating-point calculations for now.
Fix a small error in arithmetic traits.
Timer example does not stop showing-off now.
Add 32bit computations to LinearAnimation.
Extend animation time for all but 8bit types.
Rename LinearAnimation to Animation.
Rename file of Animation class.
Update LED class.
Add KeyFrame Animation class.
Adapt Indicator, Strobe and Pulse classes to using
KeyFrameAnimation.