Merge pull request #53 from ulvmoen/master

Inversion of 4D push down data
CRA-534: Fixed some small bugs and merged with nrlib.
Merge pull request #54 from gudmund-hermansen/master

CRA-534: Fixed some small bugs and merged with nrlib.
CRA-534: Fixed some warnings related to merging with nrlib.
Merge pull request #55 from gudmund-hermansen/master

CRA-534: Fixed some warnings related to merging with nrlib.
CRA-647 Bug in resampling of simbox using RMS data

Use d2 = d1*log(vp1)/log(vp2), should use d2 = d1 * vp1/vp2