[INTERNAL] allow for SplinePackages with just two data points
[INTERNAL] allow for SplinePackages with just two data points
[TEST] testing SplinePackage constructor with one and two data points
[COMMENT] comments removed
[TEST] checking linear behaviour in case of two datat points
Merge pull request #996 from lars20070/fix/SplinePackage

allow for SplinePackages based on just two data points