This improves GeoLib::SearchNearestPoints() by factor >1.4.

Cleanup mesh lib tests memory leaks

GeoLib: Rework PointVec

fix Eigen issue with auto keyword in NaturalCoordinatesMapping

Adjusting tab-order for Data Explorer dialogues

a template type was not used in some places in DenseVector

fix reading of matgroups from gmsh msh

now reads physical surface id, before read plane surface id

Reduc warnings in tests.
Thanks!  

This avoids a warning about unused argument oct_tree.

Substitution of PointVec::makePntsUnique() using an OctTree based impl.

The method is used from the friend class PointVec.

[T] Remove memory leaks in AssemblerLib tests.

GeoLib OctTree - some small improvements

OctTree modifies the right limit of the interface a little bit.

At the moment it is not possible to write
oct_tree = createOctTree()
because the copy constructor is explicitely deleted. In my point of view
it does not make sense to implement a copy constructor. Sometimes it is
necessary to recreate the OctTree, for instance if the spatial size has changed.

Cleanup in GeoLib