Port of the LINZ C functions to manage NZTM2000 projection to/from WSG84 projection
Original functions available at http://www.linz.govt.nz/data/geodetic-services/download-geodetic-software#nztm2000.
And used another port (from c# this time) at https://github.com/leighghunt/nztm/blob/master/nztm/nztm.cs.