More extensible for loading decoder

[nikotung]

Is your feature request related to a problem? Please describe.. I had come across a same as issue #29 while trying to parse some QRCodes from Phillipines based on the EMVco standard. From the issue #29, I think the example was from Sri Lanka Rupee because the country code is 144.Maybe there are some country implementing the QRcode payment system based on the EMVco specification with a slight difference.

Describe the solution you'd like to see. By default,all decoders follow the EMVco specification.Also,provide a flexible,extensible way to load another decoder for the same identifier.For example,provide a way to replace the AdditionalDataFieldDecoder,under the ID=62,with a custom decoder in the DecodersMpmMap class.This decoder should be able to decode the QRcode from Phillipines.