Extend the localisation functionality to cover new methods for scaling of correlation between fields and obs

[oddvarlia]

Extend the localisation functionality to more methods for scaling of correlation between fields and observations. New methods should be:

• Read scaling factor from file using GRDECL parameter format with float values.
• Read region parameter from file using GRDECL parameter format with integer values. User specify which regions that should be active field parameters and not active field parameters. User specify a scaling factor for each of the active regions/segments. It should also be an option to define a smoothing of the discontinuities for the scaling factor between regions.

Solution:
New options for the keyword 'method'. New sub-keywords: from_file and segment with associated keywords to supply the necessary information.