CRA-708: Fixes handling missingdata in input files for background.
Merge branch 'CRA-505' of git://github.com/CRAVA/crava into CRA-708
CRA-708: Fixed handling of padding when sampling into NRLib grid, and fixed two memory allocation errors in avoinversion.
Merge pull request #121 from RagnarHauge/CRA-505

Cra 505