timegcm/trunk:
 - Made some minor changes to metadata in the output history files
   to accomodate netcdf Climate and Forecasting conventions CF-1.0,
   with ucar.nc2.dataset.conv.DefaultConvention = _CoordSysBuilder.
 - These modifications only change and add variable and global file
   attributes, so there will be no model results changes, and 
   post-processors should still work as before.
 - This change set enables use of Unidata's IDV (Interactive Data
   Viewer) processor with timegcm history files. This was requested
   by Gang Lu, and the changes were suggested by Yuan Ho of Unidata.