Added experimental tilt and tiltDirection to the Touch interface

Source/platform/PlatformTouchPoint.h

Index: Source/platform/PlatformTouchPoint.h
diff --git a/Source/platform/PlatformTouchPoint.h b/Source/platform/PlatformTouchPoint.h
index 578f520d77140d0cdb3457b329f5f6db7c5cb18a..4dd6842ee801236ec43381ed504bdf5a4bf7adaa 100644
--- a/Source/platform/PlatformTouchPoint.h
+++ b/Source/platform/PlatformTouchPoint.h
@@ -39,6 +39,7 @@ public:
     PlatformTouchPoint()
         : m_id(0)
         , m_rotationAngle(0)
+        , m_tilt(0)
         , m_force(0)
     {
     }
@@ -49,6 +50,7 @@ public:
     FloatPoint pos() const { return m_pos; }
     FloatSize radius() const { return m_radius; }
     float rotationAngle() const { return m_rotationAngle; }
+    float tilt() const { return m_tilt; }
     float force() const { return m_force; }
 
 protected:
@@ -58,6 +60,7 @@ protected:
     FloatPoint m_pos;
     FloatSize m_radius;
     float m_rotationAngle;
+    float m_tilt;
     float m_force;
 };