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().
replaced vtkPolygons with vtkTriangles for geometric surface visualisation
Merge pull request #109 from TomFischer/ImproveGeoLibPointVec

Improve GeoLib::PointVec.
removed unused method-definitions and fixed enum mismatch
Merge branch 'master' of https://github.com/ufz/ogs
removed changes due to modified makepntsunique method
Test PointVec with empty input.
Test PointVec constructor with single point input.
Test PointVec with nullptr input.
Test PointVec with two diff input points.
Allocate vector of points instead of using reference.
Split two points test in DiffPoints and EqualPoints tests.
Test PointVec push_back() operator.
In PointVec tests move up common code.
In PointVec test add random points generator.
New maxNormDist() for points. Correct comparisons for eps=0.