CRA-545 Estimate variables for tabulated modulus rock
CRA-550 dz should be calculated for each zone in the multizone background model
CRA-552 The blocked logs in the multizone background model should contain missing values when outside the eroded grids for base and top correlation structures
Merge branch 'CRA-550'
Merge branch 'master' of https://github.com/CRAVA/crava
Merge pull request #26 from ulvmoen/master

Fixed bug in multizone background model