Removed unused remove_edge function.
Documentation.
Added get_apex function for an edge relative to a face.
Renamed edge_removal to flip_23_recursively.
Added a get_neighbour function.
Removed assertions.
Added a function which orients the nodes in a counter clockwise order.
Added remove multi face as described in Shewchuk "Two Discrete Optimization Algorithms for the Topological Improvement of Tetrahedral Meshes".

May cause inverted tetrahedra!!!