[SharpDX] Add Equal(ref other) for vector/quaternion/matrix

Equal(ref other) is now also used in == and != operators
[SharpDX] Add Vector/Scalar component-wise addition and subtraction operators/functions
[SharpDX] Remove normalization from quaternion billboard functions and always normalize input in RotationLookAt
[SharpDX] Reuse stable Matrix3x3 functions to produce quaternions.

It gives better results and protects against negative Sqrt input and division with zero (NaN)
[SharpDX] Rename VectorXXX.Modulate(..) functions to VectorXXX.Multiply(..).
[SharpDX] Vector divide operators & function for x=float/vector
[SharpDX] Add IsZero in vector to quickly check if its (exactly) equal to zero
[SharpDX] Transform Vector3 with Matrix3x3