added algorithm for removing duplicate cells
added reader for silvaco str files into 3D triangular hull meshes
Merge branch 'FlorianRudolf/feature-algorithm-remove-duplicate-cells' into next

Conflicts:
	include/viennamesh/algorithm/all.hpp
	src/viennamesh/core/algorithm_factory.cpp
Merge branch 'FlorianRudolf/feature-silvaco-str-reader' into next