CSI Magic Number

[nathanhaigh]

I've been having a look at the CSI specs and your code. Shouldn't the magic number for CSI be:

var csiMagic = [4]byte{'C', 'S', 'I', 0x1}

instead of:

var csiMagic = [3]byte{'C', 'S', 'I'}

Here: https://github.com/biogo/hts/blob/master/csi/csi.go#L16

[kortschak]

The CSI magic number is version-dependent. CSIv1 is "CSI\x01", CSIv2 is "CSI\x02". The number is written out programmatically rather than from a constant, and read similarly.