Use 0 as default braking offset

Legacy implementation of the offset to 0.5 was bugged before this PR, compatibility not needed

Author: cesarBLG

Source/Documentation/Manual/cruisecontrol.rst

@@ -101,7 +101,7 @@ A list of the available .eng file CC parameters follows here below.
    "SpeedDeltaToStopAccelerating", "Difference between train speed and set speed below which throttle is closed", "Float (speed)", "0"
    "SpeedDeltaToStopBraking", "Difference between train speed and set speed below which brakes are released", "Float (speed)", "0.5 m/s"
    "SpeedDeltaAcceleratingOffset", "Speed delta at which the demanded acceleration is 0", "Float (speed)", "0"
-   "SpeedDeltaBrakingOffset", "Speed delta at which the demanded deceleration is 0", "Float (speed)", "0.5 m/s"
+   "SpeedDeltaBrakingOffset", "Speed delta at which the demanded deceleration is 0", "Float (speed)", "0"
    "ForceRegulatorAutoWhenNonZeroSpeedSelected", "When a non zero speed is selected, the regulator is set to auto", "Boolean", "FALSE"
    "ForceRegulatorAutoWhenNonZeroSpeedSelectedAndThrottleAtZero", "Self explaining", "Boolean", "FALSE"
    "MaxForceKeepSelectedStepWhenManualModeSet", "Self explaining", "Boolean", "FALSE"

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/CruiseControl.cs

@@ -131,7 +131,7 @@ public float SetSpeedKpHOrMpH
         public float SpeedDeltaToStartAcceleratingMpS;
         public float SpeedDeltaToStopAcceleratingMpS;
         public float SpeedDeltaAcceleratingOffsetMpS;
-        public float SpeedDeltaBrakingOffsetMpS = -0.5f;
+        public float SpeedDeltaBrakingOffsetMpS = 0;
         public bool DynamicBrakePriority = false;
         public List<int> ForceStepsThrottleTable = new List<int>();
         public List<float> AccelerationTable = new List<float>();