temp bugfix for helperbounds not handling ref data correctly

[giannou]

checkMin and checkMax tests have been wrong all this time due to this line:

iamc/R/helperBounds.R

Line 2 in c4849cf

x$ref <- cfg[[type]][x$variable]

Here's a suggested quickfix.

[giannou]

Thanks, merging now. Since the package is not part of pik-piam, I'm not sure how building and publishing the corrected version on the PIK-CRAN will work.

[tscheypidi]

@giannou Oh, good point. It is actually the same procedure as for packages on pik-piam. But that also means that you have to run buildLibrary to increase the version number and have the update automatically distributed via PIK-CRAN. Can you create another PR after running buildLibrary?