CONTRIB: Add note about the origin of the idxint type
CONTRIB: Add note about the origin of the idxint type

It is from ECOS and used in the export FMU code.

necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,tulip-control/tulip-control