#7 unable to read related unit

[Viktor Stoehr]

Hi Christian,

we are unable to load related units for measured quantities if the relation information is stored at AoMeasurementQuantity instances and the inverse relation is omitted at the AoUnit instances.

I have attached a patch, which worked in my tests. Please give it a look.

[Christian Rechner]

Thanks for the patch! I have released a new version of the lib including the patch.