The embryo of a matrix class has been implemented. It is still based on Array2D and therefore the indexing is still 0 to n-1 instead of being 1 to n and the coordinates are swapped compared to normal matrices.

New regression models have been added, all based on the linear regression code but using variable transforms to achieve their goal. 

The global header file (MeteoIO.h) was incomplete. It has therefore been reorganized and now contains everything that it should...