Removed completed TODOs.

Basis_Function.py

@@ -2,9 +2,6 @@
 """
 @author: Laura C. Kühle
 
-TODO: Contemplate whether calculating projections during initialization can
-    save time -> Done (solved due to property attributes)
-
 """
 import numpy as np
 from sympy import Symbol, integrate

DG_Approximation.py

@@ -11,11 +11,6 @@ TODO: Contemplate moving stiffness and boundary matrix from update scheme
     to basis
 
 Urgent:
-TODO: Investigate protected vs. public variables -> Done
-TODO: Investigate decorators and properties -> Done
-TODO: Investigate how to make variables read-only -> Done
-TODO: Replace getter with property attributes for basis -> Done
-TODO: Contain polynomial degree in basis -> Done
 TODO: Improve docstring for Basis class
 TODO: Enforce abstract classes/methods (abc.ABC, abc.abstractmethod)
 TODO: Introduce Mesh class