Add electromechanical brake model

[mforets]

cc: @dfcaporale

Reference:

• Verifying properties of an electro-mechanical break system. Thomas Strathmann and Jens Oehlerking

[mforets]

The paper presents different versions of the model:

• nonlinear, continuous
• linear, continuous
• linear, discrete; PI controller, PWA hybrid automaton

We can have one notebook per model, under the same folder /ElectroMechanicalBrake.