getaffine bug?

[JohnAshburner]

I've recently started dabbling with Julia and find the NIfTI module quite useful. I hope you don't mind me feeding back any bugs as I find them. One I've found so far is that the getaffine function should perhaps use pixdim[4], rather than bitpix[4].

elseif h.qform_code == 0
    # Method 1
    return Float64[
         pixdim[2] 0         0          0 0
                   0 pixdim[3]          0 0
                   0         0  bitpix[4] 0
                   0         0          0 1
    ]