Import GPR data link is broken

[TheCre8r]

On the Readme.md file the Import GPR data link is broken

See tutorial [Import GPR data](http://emanuelhuber.github.io/RGPR/00_RGPR_import_data/).

Thanks!

TC

[emanuelhuber]

Thank you very much, TC, for reporting this broken link!
I fixed it!
Do not hesitate to contact me if you have any question or if you need some specific functionalities.
Best,
Emanuel