Patch 1.6.4

Resolve "Change zs defaultvalue in snow_detector"

See merge request !54

Resolve "Fix zs computation while using DEM with nodata"

See merge request !53

Merge branch '66-zs-computation-method-return-1-when-error-occur-whereas-1-is-a-valid-zs-value' into 'release-1.6'

Resolve "zs computation method return -1 when error occur, whereas "-1" is a valid zs value"

See merge request !52

Merge branch '66-zs-computation-method-return-1-when-error-occur-whereas-1-is-a-valid-zs-value' of https://gitlab.orfeo-toolbox.org/remote_modules/let-it-snow into 66-zs-computation-method-return-1-when-error-occur-whereas-1-is-a-valid-zs-value

Merge branch '66-zs-computation-method-return-1-when-error-occur-whereas-1-is-a-valid-zs-value' into 'release-1.6'

Resolve "zs computation method return -1 when error occur, whereas "-1" is a valid zs value"

See merge request !51

Resolve "Forbid having zs not in range [-413; 8850]"

See merge request !50

Resolve "Fix z_center cast in histo_utils.cxx"

See merge request !49

Merge branch '61-landsat-snow-product-are-not-recognized-when-provided-by-muscate' into 'release-1.6'

Resolve "Landsat snow product are not recognized when provided by muscate"

See merge request !46