VERY IMPORTANT: Corrected Matlab scripts for grid nesting configuration

[arango]

Several of the Matlab scripts for grid nesting were updated:

• contact.m: Modified substantially the refinement function. An interpolation mapping is carried out instead to determine the coarser donor grid containing the finer grid contact points and physical boundary determination for U- and V-points. We need to use the UV-perimeter instead of the PSI-points perimeter to avoid round off in the inpolygon intrinsic Matalab function. This is extremely important to get correct results!!!

• grid_perimeter: Added the UV-perimeter to the grid sub-structure. This field is very important when determining the contact points at the physical boundaries of the nested grid. Also, added fractional (XI, ETA) coordinates at PSI-, RHO-, U-, and V-points to the grid sub-structure.

WARNING, WARNING, WARNING: In order for ROMS to work with nesting, you must update the Matlab nesting scripts in this repository and recompute the contact points NetCDF file.v Otherwise, your nesting application will not work because incorrect nesting contact points indices...