CRA-754:
In commondata constructor: Made it possible to bypass background model generation in estimation mode.

CommonData::CheckThatDataCoverGrid: Fixed output of angle to degrees.

In CommonData::CheckThatDataCoverGrid: fixed offset handling, as this is for seismic grids, and thus shifted 0.5 grid cell.
Merge branch 'CRA-754'
Merge pull request #177 from RagnarHauge/master

CRA-754: Some small fixes