CRA-584, CRA-593: Started on priormodel 3D. Started on replacing fftgrid to NRLib::Grid in ReadGridFromFile.
CRA-581, CRA-585, CRA-593. Added changes for Gravimetric. Added the new resample algorithm to CommonData, with NRLib Grid as input.
CRA-561, CRA-593: Fixed Prior Facies Cubes for multiple intervals. Added intervals to ReadGridFromFile.
CRA-559: Fixed trend-cubes, replaced FFTGrid with Grid.
CRA-568, CRA-587: Fixed ReadGridFromFile for Velocity and RMS-data in traveltime.
CRA-568, CRA-593: Set up background model to use Grid both in CommonData and Background.cpp.
CRA-571, CRA-584: Set up prior model in main.
CRA-559, CRA-596: Moved TrendCubes to multiintervalgrid. Started on ModelGeneral for intervals
CRA-596: Started on ModelGeneral for intervals.
Merge pull request #41 from hgolsen/CRA-505

Cra 505