New Windows executable. Includes code to implement https://github.com/NAVADMC/SpreadModel/issues/134 . Ready to test with https://github.com/NAVADMC/SpreadModel/issues/149
Now does only 1 iteration (regardless of number of runs parameter) when the -i (starting iteration number) command-line option is used. As requested in issue https://github.com/NAVADMC/SpreadModel/issues/149
Merge branch 'master' into Windows