Provide methods capable of handling supplementary characters in DecimalFormatSymbols

These methods (and their setters) are currently only capable of dealing with chars within the BMP:

getDecimalSeparator()
getDigit()
getGroupingSeparator()
getMinusSign()
getMonetaryDecimalSeparator()
getPatternSeparator()
getPercent()
getPerMill()
getZeroDigit()

Equivalent set of methods that deals with 'int" should be provided, and the "char" versions should be deprecated.