fun currencyFormatter(maxDecimals: Int, minDecimals: Int): NumberFormat
Create a number formatter for use with converting currency to strings. This probably isn't needed externally since the other formatting functions leverage this, instead. Leverages the default rounding mode for zec found in ZEC_FORMATTER.
maxDecimals - the number of decimal places to use in the format. Default is 6 because ZEC is
glorious.
minDecimals - the minimum number of digits to allow to the right of the decimal.
Return
a currency formatter, appropriate for the default locale.