Updated plotting package, hbackground.F

[arango]

Updated file hbackground.F for ROMS plotting package to add the new changes for common block mapcm1 in the NCAR's library version 5.2.0. I can believe that they continue making changes to this common block once in a while. It is annoying because the library is not backward compatible.

A new cpp option NCARG520 is introduced in the makefile to allow compiling with this version of the library.

Many thanks to Simon Spagnol for ​providing us his updated hbackground.F for this new version of the libray.

I am also using the logical flag lmask in mskcle.F to avoid land/sea masking, if wanted, when lmask=0 even if there is a land/sea masking array in the input NetCDF. In this way, the user may utilize this standard input parameter for land/sea masking behaviors in the plot. This is useful when plotting the raw bathymetry with the gebco palettes. It allows to color land with the appropriate values of the topography. The lmask=1 paints the land with a solid color. Of course, the hraw variable, record 1, needs to have positive values in the land and negative values in the water. Recall that the bathymetry used in ROMS, variable h, has the water values positive and the land is cropped to a constant positive value greater than zero. The variable hraw is never used in ROMS. Many users ignore this variable. I always like to write in record 1, the original topography before cropping and smoothing. In this way we save the starting raw topography for future reference.