Optional calibration in PV wrapping
Calibration is only needed to correct laser ids so that they increase upward from 0 to N. However, we don't really care if these laser rings are not properly sorted, as SSKE considers each ring independently from other ones.
Note that laser IDs are already correctly ordered for Ouster data. Such calibration might only be needed for Velodyne data.
To simplify user interface, this second entry is hidden from selection dialog. It can still be accessed later by manually changing inputs.
If calibration input is empty (such as for HDL64), or if the vertical angle array isn't available, calibration is ignored.
This fixes using HDL64 data with PV wrapping, where calibration is empty.
NOTE: If the laser IDs values become important (for example if SSKE becomes based on a range image or vertex map - such as in !104 (closed) - and if above and below neighbor scan lines are used too), then we should reconsider this optional input.