Added a function which checks for inverted tetrahedra in a set of tetrahedra.
Deleted some min_quality functions (using min_quality of a set of tetrahedra instead).
Removed check for inverted tetrahedra from min_quality function. Checking for inverted tetrahedra is now only done where necessary.
Created a get_tet function and used it when doing connected component analysis for improving speed.
Clean up in topological face removal functions.
Minor clean up in topological face removal.
Created a function which returns the barycenter of a set of nodes.
Improved the speed of the smart laplacian smoothing.
Generalized the precond_smooth function to compute the minimum tetrahedral quality when moving a node.
Created more min_quality functions which takes a set of faces and and a new position as input.
Uses the new min_quality function when checking how to collapse an edge.
Minor clean up in collapse function.
More clean up and performance improvements in collapse function.
Yet more clean up and performance improvement of collapse edge function.
Removed old functions for checking if a tetrahedron is inverted.

The boundary and co boundary of a simplex no longer need to be sorted.