code: public Matrix3f rotate(float ang, float x, float y, float z) {
          return rotate(ang, x, y, z, this);
      }
docs: Apply rotation to this matrix by rotating the given amount of radians
  about the given axis specified as x, y and z components.
  <p>
  The axis described by the three components needs to be a unit vector.
  <p>
  When used with a right-handed coordinate system, the produced rotation will rotate a vector
  counter-clockwise around the rotation axis, when viewing along the negative axis direction towards the origin.
  When used with a left-handed coordinate system, the rotation is clockwise.
  <p>
  If <code>M</code> is <code>this</code> matrix and <code>R</code> the rotation matrix,
  then the new matrix will be <code>M * R</code>. So when transforming a
  vector <code>v</code> with the new matrix by using <code>M * R * v</code>
  , the rotation will be applied first!
  <p>
  Reference: <a href="http://en.wikipedia.org/wiki/Rotation_matrix#Rotation_matrix_from_axis_and_angle">http://en.wikipedia.org</a>
  
  @param ang
  the angle in radians
  @param x
  the x component of the axis
  @param y
  the y component of the axis
  @param z
  the z component of the axis
  @return this