when enumerating groups, 127 is encoded as 7f but 128 and following are encoded as
ff:ff:ff:80 ... this is an ugly hack to compensate for this ... no idea why it is required,
looking at the asn documentation it would seem to me that this was not necessary.
Merge pull request #2 from oetiker/asn-ff-integer-hack

when enumerating groups, 127 is encoded as 7f but 128 and following are ...