Removed completed TODOs.

DG_Approximation.py

@@ -3,13 +3,6 @@
 @author: Laura C. Kühle
 
 Discussion:
-TODO: Ask whether cell averages/reconstructions should be contained in basis
-    -> Done (yes, hard-code simplification)
-TODO: Contemplate whether basis variables should be public -> Done (yes)
-TODO: Contemplate a Mesh class
-    (mesh, cell_len, num_grid_cells, bounds, num_ghost_cells, etc.)
-    -> Done (yes)
-TODO: Contemplate to contain polynomial degree in basis -> Done (yes)
 
 Urgent:
 TODO: Hard-code simplification of cell average/reconstruction in basis
@@ -20,13 +13,6 @@ TODO: Introduce Mesh class
 TODO: Check whether ghost cells are handled/set correctly
 TODO: Find error in centering for ANN training
 TODO: Investigate g-mesh(?)
-TODO: Extract do_initial_projection() from DGScheme -> Done
-TODO: Move inverse mass matrix to basis -> Done
-TODO: Extract calculate_cell_average() from TCD -> Done
-TODO: Improve calculate_cell_average() -> Done
-TODO: Extract calculate_[...]_solution() from Plotting -> Done
-TODO: Extract plotting from TCD completely
-    (maybe give indicator which plots are required instead?) -> Done
 TODO: Contain all plotting in Plotting
 TODO: Remove use of DGScheme from ANN_Data_Generator
 TODO: Clean up docstrings