Parsing options for the Convert report from the command line.
Default starting options for the Convert report. After considering what is parsed in from the command line and price data, a Convert.Opts will be generated.
Is the target commodity determined by the user or automatically?
Do not be tempted to change the setup in this module so that the individual functions such as parseColor and parseBackground return parsers rather than OptSpec. Such an arrangement breaks the correct parsing of abbreviated long options.