Substituted assert using exception. Added docu.

Using std::invalid_argument exception instead of assert leads to
error messages both in release and debug version.
Added exception to handle invalid input and docu.

Added exception std::invalid_argument to constructor of class template TemplateVec.
Made documentation more specific.
In PointVec::makePntsUnique simplify removing nullptr in pnt_vec.

Conflicts:
	GeoLib/PointVec.cpp
Removed call by ref in PointVec::makePntsUnique().
Merge pull request #109 from TomFischer/ImproveGeoLibPointVec

Improve GeoLib::PointVec.