Minor fixes and improvements of the YOGA-controller+matlab-simulator model

[nunoguedelha]

Follow-up of:

TO-DO

• Restore "measured joint torques" in the scopes visualizer.
• When Config.EMERGENCY_STOP_WITH_ENCODER_SPIKES is OFF, at least a warning is triggered by joint encoder spikes.

[nunoguedelha]

When Config.EMERGENCY_STOP_WITH_ENCODER_SPIKES is OFF, at least a warning is triggered by joint encoder spikes

1. Replaced the boolean flags Config.EMERGENCY_STOP_WITH_JOINTS_LIMITS and Config.EMERGENCY_STOP_WITH_ENCODER_SPIKES by enumerations (None, Warning, EmergencyStop).

2. The "Assertion" block was replaced by a "Variant Sub-system" in order to trigger either a Warning or a Stop.

3. Simplified the function wbc.checkInputSpikes(...), also removing the use of persistent instruction. Instead, two inputs were used (u and u_prev), as we can se in the above diagram.