[geostatistic] moved geostatistic to own sub-module
added variogram class
[variogram] implemented orthodrome calculations
[variogram] implemented orthodrome calculations
[variogramm] paired distance calculations
[variogramm] paired distance calculations
adapted license testing
minor
[data] implemented 2D suppert in get_valid data(); [geostatistic] initial implementation of new semivariogram plotting
[data] minor bugfix for 2D get_data
slightly more effiicent implementation of variogram calculation (no squared distance matrix)
[geostatistic] pre-filtering of distance prior to variogramm calculation
cleanup
[variogram] cythonized variogram base class
added compilation of variogram cython code
[variogram] again slight speedup
[variogram] really fast implementation now using ndarrays; furhter tuning on semivariogram as such needed
adapted faster variogram calculations
some clean up
[test_geostatistic] bugfix