Added MeshGeoToolsLib folder for new lib and CMakeLists.txt.
Added implementation from OGS-5.

- changed some data structures to fit with OGS-6
- remove unused code fromm OGS-5 implementation
Added test for MeshNodeSearcher.
[MeshNodeSearcher] Calculation of mesh specific search length.
Changed data type to pointer because older compilers are complaining about this.

The data type of the std::vector needs a copy constructor. Since class
MeshNodesAlongPolyline has const reference member functions older compilers
do not generate the copy constructor properly. Once we all have newer
compilers we can change it back.
Added cast to proper type and check result of cast.
Added forward declaration and missing includes.
Fixed memory leaks in test for mesh node search.
Output the calculated search length of a mesh as requested by Nori.