Uptated matlab/4dvar scripts

[arango]

I updated several of the 4D-Var Matlab processing scripts:

• obs_ijpos.m: added additional arguments Ioffset and Joffset that can be used to control the polygon defined by the application grid. This can be used to avoid processing observations next to the grid boundaries, if so desired:

      Ioffset(1):  I-grid offset on the edge where Istr=1
      Ioffset(2):  I-grid offset on the edge where Iend=Lm
  
      Joffset(1):  J-grid offset on the edge where Jstr=1
      Joffset(2):  J-grid offset on the edge where Jend=Mm
  

• d_sst_merge.m: New driver template to merge several SST ROMS 4D-Var observations NetCDF files. It allows the user to merge data from several satellites and process super observations.

• load_sst_AMSRE.m: New script to extract AMSRE satellite sea surface temperature for the period of interest and specified region from ROMS Grid file. The SST data is from the OpenDAP catalog maintained by NOAA PFEG CoastWatch in California. The resolution is 0.025 degree global 1-day average product.

Many thanks to Andy Moore for suggesting these updates.