missing import in geoplot.discrete_cmap2
fgmax_tools: fix fname to input_file_name
dtopotools.convert_to_standard_units should loop over input_units keys
change number of fgmax grids allowed from 2 to 5 by default
Merge pull request #121 from rjleveque/fix_5.2.1

Fix 5.2.1
fixed a number of bugs in fgmax_tools.py for point_styles other than 2, which had not been exercised
Merge pull request #123 from rjleveque/fgmax_tools_fix

fixed a number of bugs in fgmax_tools.py