ADDED: more prototypes
ADDED: more prototypes and declarations for various methods
ADDED: some factories and implementations
ADDED: 
directed EdgeRings,
FacetEdges have links to DirectedEdgeRings now, 
tuples of DirectedEdgeRings are composed to EdgeRings
CHAGED:

refactored dependencies EdgeRing -> DirectedEdgeRing
CHANGED:
tried some things in context with assertions
ADDED:
a lot of implementations
ADDED:
Imlementations and tests for EdgeRings
TODO:
Fix this:
../Subdiv3/TestManifold.cpp:148: Failure
Value of: 3
Expected: ring->computeEdgeRingSize()
Which is: 1
[  FAILED  ] Manifold.EdgeRingLinking (0 ms)
[----------] 5 tests from Manifold (0 ms total)
FIXED:  Bug in triangle topology
ADDED: binary file to gitignore
MERGED: adopted changes from imported branch
ADDED: tried to implement something like makeTetraeder
DELETED: binary
no compiler errors any more
ADDED: a few lines for tet construction
ADDED: .. some more lines for tet construction
ADDED: more functs for tetrahedron topology
ADDED: Destructor
ADDED: implmentations for vertex edge linking on a non manifold vertex
ADDED: 
implemented missing subfuncts
Vertex.cpp
CHANGED:
 Vertex hold pointer to DirectedEdgeRing
 FacetEdge holds pointer to directedEdgeRing
 DirectedEdgeRing hold pointer to Vertex
ADDED: some test for manifold