Axivity AX3 demo file does not process with g.cwaread (anymore)

[vincentvanhees]

It seems http://www.axivity.com/files/resources/longitudinal_data.zip
cannot be processed with g.cwaread. I am pretty sure it worked at some point.

Maybe the cwaread updates earlier this year broke this functionality. I think I have a fix and will make PR later today or tomorrow.