The rewrite continues.
Adds example ANL dataset and T2K data set for testing.
Begins adding weight engines, but nothing functional yet.
Extensive rewrite of Histo utilities. They are a bit excessive now, blame ROOTs
inconsistency.
ISimpleDataSample can now use TH2Polys, after much effort, if you get
anything slightly wrong, welcome to a world of template substitution errors...