mo_grid: replace ceiling with nint

Merged Sebastian Müller requested to merge muellese/mhm:ceil_grid_bugfix into develop

Fixes #126 (closed) #131 (closed)

Fortran intrinsic ceiling was used to calculate Ncols, Nrows which is now done by nint in order to be stable when cell factor is close to 1.

Edited by Sebastian Müller

Merge request reports