Develop link between icesDatras package and DTU DATRAS package

[colinpmillar]

Summary

provide DATRASraw objects from icesDATRAS so the user of icesDatras does not have to use the php download script (https://github.com/DTUAqua/DATRAS/blob/master/DATRAS/inst/datras.php) to access data

Tasks required

• [x] fork DATRAS from DTUAqua github
• [x] attempt to recreate examples / demo's using icesDatras

Links to other issues?

[colinpmillar]

Done - pull request accepted by Kasper :)