'**DESCRIPTION**
Rotate the image 90 degrees to the left, the same as 270 degrees to the right.
This is the same as rotateRight()
**RETURNS**
A SimpleCV image.
**EXAMPLE**
>>>> img = Image(\'lenna\')
>>>> img.rotate90().show()'

def rotate90(self):

    retVal = cv.CreateImage((self.height, self.width), cv.IPL_DEPTH_8U, 3)
    cv.Transpose(self.getBitmap(), retVal)
    cv.Flip(retVal, retVal, 0)
    return Image(retVal, colorSpace=self._colorSpace)
