Added new SimplexSet class which is intended to replace the simplex_set class.
Added get_boundary and get_co_boundary functions using the SimplexSet class.
Deleted the unused split tetrahedron function.
Extended the functionality of SimplexSet and created a test case.
Minor clean up in Simplex class.
Replaced template getters for boundary and co boundary with explicit functions.
Added an is_neighbour function for nodes and clean up in the existing is_neighbour function.
Bugfix in get_co_boundary functions.
Implemented the 2-2 flip (can also be used as 4-4 flip).
Using flip 4-4 when performing 2-2 flip.
A bit of clean up in swap function.
Added a - operator between SimplexSet and a key.
Added a test of collapse and split in the DSC class.
Added test of 2-3 flip and 3-2 flip.
Flip 3-2 and flip 2-3 returns face key and edge key respectively.
Clean up in flip 3-2.
Clean up in flip 2-3 and flip 3-2 functions.
Deleted log files.