Scan order

This MR unravels a little bit our scan structure, to allow simpler meta scans and less verbose structure. This is not the end, but a start to do that.

This MR helps addressing issues: #179 (closed) #174 (closed) #86 (closed) and solves: #121 (closed) It was tested with a meta scan tuning and digital scan; still regressions are rather likely.