DN2TOARadiance() now returns float32 radiance instead of float64. Bugfix in Orthorectifier._get_common_extent(). Revised Geometry_Transformer and Geometry_Transformer_3D classes. Updated minimal version of sensormapgeo which makes the orthorectification much faster (factor 6-10) and fixes the deadlock within sensormapgeo.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>