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.
Adapt STM32F4 Discovery Timer example for animations.
Rename Pulsar -> Pulse.
Fix wrong register bit name
Fix Animation computations for 8bit values.
Fix KeyFrameAnimation repeat count and current frame position.
Make KeyFrameAnimation work with multi-channel values.

A KeyFrame may now hold more than one value.
And the KeyFrameAnimation can now use more than one
animator at a time.

The use case here is the fading of an RGB LED, where three channels are controlled at the same time.
The KeyFrames can now be specified more efficiently for this.
ext: replace old STM libs with new CMSIS from STMCube
STM32: clock: use new register names
STM32: gpio: use new register names