Missing implementations

[speps]

A few missing implementations (declared in SimplicialComplex.h but no method body in the .cpp file) :

• VertexHandle nextVertex(const FaceHandle&face, const VertexHandle& curVertex) const;
• VertexHandle prevVertex(const FaceHandle&face, const VertexHandle& curVertex) const;
• EdgeHandle nextEdge(const VertexHandle& vert, const EdgeHandle& curEdge) const;
• EdgeHandle prevEdge(const VertexHandle& vert, const EdgeHandle& curEdge) const;
• FaceHandle nextFace(const EdgeHandle& edge, const FaceHandle& curFace) const;
• FaceHandle prevFace(const EdgeHandle& edge, const FaceHandle& curFace) const;
• TetHandle nextTet(const FaceHandle& face, const TetHandle& curTet) const;
• TetHandle prevTet(const FaceHandle& face, const TetHandle& curTet) const;