Added several Matlab scripts to repository

[arango]

Added several new Matlab scripts to the repository:

• forcing/add_heatflux.m: Adds the heat flux components (shortwave, longwave, latent, and sensible) to an existent NetCDF file if not present. The file must contain the net surface heat flux variable so it can be used as metadata for the heat flux components. It is primarily used to write field from coupling during debugging.

• netcdf/nc_stats.m: Computes the statistics of requested NetCDF variable for the specified record(s). If land/sea mask is available, it computes the statistic for the water points only. I can be used to determine global colormap dynamical range for animations.

• netcdf/nc_time.m: Reads the time variable from the specified NetCDF file, and computes the elapsed time since the specified reference date. If the time record (Tindex) is omitted, it processes all the available records.

• utility/roms_field.m: Computes requested secondary 2D or 3D field from ROMS state output history/average data. Currently, there is code for compute 2D or 3D relative vorticity.

• utility/rvorticity.m: Computes 2D or 3D relative vorticity from ROMS fields.

• utility/vector4stream.m: Given velocity components and grid information, it interpolates data to a monotonic and plaid grid (as if produced by MESHGRID) for the plotting of streamlines elsewhere using streamslice qor 'm_streamline'. The user may specify the monotonic grid corners bounded by (Llon,Blat) and (Rlon,Tlat).

• utility/wrt_latlon.m: Writes the (lat,lon) pairs into an ASCII so it may be used in the ROMS plotting package.

• Updated landmask/edit mask.m to improve the logic of the coastline file to use. Many thanks to John Warner for bringing this to my attention.