Made sqrLength() private.

Method does not make use of any part of Vector3.
If the functionality is needed it can be impl. outside of this class.

The TemplateVector3 is derived from TemplatePoint<T,N>. There isn't a
constructor taking 3 values for TemplatePoint. Instead of this a std::array
is used to initialize the TemplatePoint data structures. For this reason
the TemplateVector3 constructor that is taking two points to initialize
the internal data needs an initializer list.

- Implemented class template GeoPoint (see GeoLib/Point.h) and substituted class templates in the typedef.
- Some changes due to changed namespace in MathLib/Vector3.h and GeoLib/Color.h.

This reverts commit 05677165.

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

- changed function scpr - for vectors of size 3 there is a specialisation of the function template which avoids OpenMP technique for very small vectors

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()

- added test programm for solving a linear system with CG-method
- time measurement is at the moment OS dependent!
- added Base folder
- added GeoLib folder
- added files in MathLib folder - restructured MathLib folder