Clang format run on near-the-header lines.

Happy New Year

Also remove unneeded default dtors.

This is automatic replacement with
ag '(?<!std::)size_t(?!\w)' --ignore-dir=ThirdParty -l | xargs perl -pi.bak -e  's/(?<!std::)size_t(?!\w)/std::size_t/g'

Using std::array-constructor version of Point3dWithID, which is the base class of Node.

Using unique type for id fixes some warnings.

Changed the base class from PointWithID to MathPoint. Also introduced a
std::size_t _id for the id of the Node.

This change saves 8 bytes per MeshLib::Node because the Node is not anymore a GeoObject.

added functionality to find all nodes that are connected via edges and via element to other nodes; replaces all cout's with appropriate logog messages

fixed gmshinterface; fixed mesh copy constructor; fixed layer mapping; removed various TODO6 tags. DIRECT STs still not working; FEFLOW and TETGEN still not working; getsurface still not working

This reverts commit 05677165.

Conflicts:
	FileIO/XmlIO/XmlGspInterface.cpp
	README.md

renamed namespace GEOLIB to GeoLib in order to be consistent with other OGS-libraries and directory names

- renamed method to access coordinates from getData() to getCoords()

changed size_t to unsigned; included a few (yet unimplemented) methods for mesh-consistency checking

added some basic functionality (get, add, etc.) and introduced an example finite element class for tetrahedra