Removed completed TODOs.

DG_Approximation.py

@@ -7,7 +7,6 @@ TODO: Contemplate saving 5-CV split and evaluating models separately
 TODO: Contemplate separating cell average and reconstruction calculations
 
 Urgent:
-TODO: Move calculate_cell_average() to Basis -> Done
 TODO: Hard-code simplification of cell average/reconstruction in basis
 TODO: Make basis variables public (if feasible)
 TODO: Contain polynomial degree in basis
@@ -15,7 +14,6 @@ TODO: Introduce Mesh class
     (mesh, cell_len, num_grid_cells, bounds, num_ghost_cells, etc.)
 TODO: Check whether ghost cells are handled/set correctly
 TODO: Find error in centering for ANN training
-TODO: Investigate g-mesh(?)
 TODO: Remove use of DGScheme from ANN_Data_Generator
 TODO: Adapt TCD from Soraya
     (Dropbox->...->TEST_troubled-cell-detector->Troubled_Cell_Detector)
@@ -25,6 +23,7 @@ TODO: Combine ANN workflows
 TODO: Add an environment file for Snakemake
 
 Critical, but not urgent:
+TODO: Investigate g-mesh(?)
 TODO: Force input_size for each ANN model to be stencil length
 TODO: Use full path for ANN model state
 TODO: Enforce abstract classes/methods (abc.ABC, abc.abstractmethod)