Add grip button axis support using Unity 2018

* App built with Unity 2018 and run on Focus 3
* Using Wave SDK 3.2 and patch files

Author: ChengNan Yang

Assets/HTC.UnityPlugin/VRModule/Modules/WaveVRModule.cs

@@ -625,7 +625,10 @@ private void UpdateDeviceInput(uint deviceIndex, WaveVR_Controller.Device device
 
                 var triggerAxis = deviceInput.GetAxis(WVR_InputId.WVR_InputId_Alias1_Trigger);
                 var touchAxis = deviceInput.GetAxis(WVR_InputId.WVR_InputId_Alias1_Touchpad);
+                var gripAxis = deviceInput.GetAxis(WVR_InputId.WVR_InputId_Alias1_Grip);
+
                 currState.SetAxisValue(VRModuleRawAxis.Trigger, triggerAxis.x);
+                currState.SetAxisValue(VRModuleRawAxis.CapSenseGrip, gripAxis.x);
                 currState.SetAxisValue(VRModuleRawAxis.TouchpadX, touchAxis.x);
                 currState.SetAxisValue(VRModuleRawAxis.TouchpadY, touchAxis.y);
             }