Added item to TODO list.

TODO.txt

@@ -11,3 +11,5 @@ Tests:
 Report:
 - Cited to VTK book, is this ok if I didn't read it?
 - Normalize coordinates between (0.0, 0.0) and (1.0, 1.0)?
+- Experiment met Processing-Python code port nog wel beschrijven of uberhaupt
+  weglaten?