#4 Support NZ voting system

[James SF DeLaHunt]

I'd like to see this tool support the precise voting system recently adopted as an option for New Zealand elections. They describe it as "Single Transferable Vote with counting by Meek's method". Details at:

<http://www.dia.govt.nz/diawebsite.nsf/wpg_URL/_6a9in6rrle9hmabbdc5q6asj9c5m2qkqkaomkirj6dtp6qobkd5nmsbadclimm09cecmkqpbkd1nm8_?OpenDocument>

From a brief examination of STV.java, it looks like the differences will be in details:
* using the specified decimal precision
* using the specified way to resolve ties etc.
* treating informal ballots the specified way

Perhaps the best structure is to create a new class STV_NZ that is parallel to STV, which implements the New Zealand method. There will also need to be changes to Table to modify error handling for informal ballots, and to the command line parameter handling.