CRA-765: Fixed bug with writing of segy-files without regarding offset. Also fixed speed for resampling of SEGY-files in background.
Merge branch 'CRA-765'
CRA-761: Rewrote resampling so that optimal padding lengths are used, and fft-plans recycled.

CRA-766: Added seismic shift to remainig well sampling algorithms.
Merge pull request #181 from RagnarHauge/master

Set of fixes> CRA-761: Faster resampling of result, CRA-765: Add SEGY-shift to written files, CRA-766: Fix esismic shift in wells