Removed commented OGS-5 code form ProcessInfo.{cpp,h}.
Removed unnecessary include and forward declaration.
Using reference instead of full copy.
Adding include in the test instead of the xml interface impl. file.
Creating GEOObjects or GEOModels instance within class ProjectData.

As a consequence removed the method ProjectData::setGEOObjects().
Moved managing of ProjectData one level deeper in the inheritance hierarchy of XMLInterface.
Using GEOObjects instances directly instead of always fetching it from class ProjectData.
Changed sequence of arguments (output,input) -> (input,output).
Moving Qt dependencies out of XMLInterface to XMLQtInterface.
Moved XML implementations deploying Qt stuff into subfolder.
[XmlCndInterface] readFile() interface change!

- readFile() put the read data into instance of ProjectData instead of a vector.
- For the same reason readConditions() was changed.
- The data is not added via the ProcessModel::addCondition() anymore!
Removed useless const specifier for return value.
Use call by reference to omit a copy.
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.