Fix: use relative file paths

[fuelflo]

Hey,

I updated those file paths to relative file paths in order to be able to compile updateStations.go and metar.go on different machines without having to adjust the source files.

However I'm not sure if this could cause other troubles or, as I used Unix relative path names, if this also works when compiling in a Windows environment.

Best regards

[esperlu]

Hi Florian,

Thanks for your input. I see your point and I will put the dataFile const as an argument to the updateStations. This will make it more "scriptable", on all platforms. I will work on that in Aug.

On my things-to-do list I will also make use of the Go's new (since 1.14) package and dependencies management system. I am a bit tired of moving different packages to and from my GOPATH.

Cheers,

Jean-Luc