[2% bonus] Constrained DT and Refinement

[taiya]

In the class matlab folder you can find ex_delaunay.m that realizes the algorithm described on this slide:

The two tasks for this bonus question are (1% each):

1. modify the script above to compute the constrained Delaunay triangulation of an input closed boundary (e.g. use dragon.mat)

2. modify the script to compute the Delaunay refinement (with a given triangle quality criteria):

The results of the two steps should be analogous to the two bottom images in this figure:

Note: if you intend to attempt working on this bonus, please declare your intention by replying to this issue. Only one correct implementation will be accepted.