Add ABS function

When braking, we check every 50 milliseconds whether the wheel is locked and if it is locked, we turn off the brake

src/vehicles/Vehicle.cpp

@@ -860,6 +860,16 @@ CVehicle::ProcessWheel(CVector &wheelFwd, CVector &wheelRight, CVector &wheelCon
 #endif
 			}
 		}
+        else {
+            if(pHandling->bABS && brake != 0.0f && brake < 1.0f && brake > adhesion) {
+                if((uint16)m_fBrakeABSTimer[wheelId] < CTimer::GetTimeStepInMilliseconds()) {
+                    m_fBrakeABSTimer[wheelId] = 50;
+                    brake = adhesion;
+                } else {
+                    m_fBrakeABSTimer[wheelId] -= CTimer::GetTimeStepInMilliseconds();
+                }
+            }
+        }
 
 		if(brake > adhesion){
 			if(Abs(contactSpeedFwd) > 0.005f)

src/vehicles/Vehicle.h

@@ -277,6 +277,7 @@ public:
 	CStoredCollPoly m_aCollPolys[2];     // poly which is under front/rear part of car
 	float m_fSteerInput;
 	eVehicleType m_vehType;
+    float m_fBrakeABSTimer[4];
 
 	static void *operator new(size_t) throw();
 	static void *operator new(size_t sz, int slot) throw();