Report Error (go die) if no geometries could be captured from rectpack output.

Other minor changes.
Port of basic dimensions class to 3D.
Dims Functors ported to 3D.

reverse renamed to rotate, to allow for a circular iteration over possible rotations and catch callers to the old function which assume only two possible rotations.
Correction on the interpretation of minDim

We need one of these functions for each dimension beyond the first one (2D needs one, 3D needs two and so on).
New 3D DimsFunctors.
Fixed small memory leak in minDimPairs.
Port of rectangles to 3D.