Removed completed TODOs.

DG_Approximation.py

@@ -22,9 +22,6 @@ TODO: Discuss referencing info on SSPRK3
 TODO: Discuss name for quadrature mesh (now: grid)
 
 Urgent:
-TODO: Unify use of 'length' and 'len' in naming -> Done
-TODO: Unify use of 'initial_condition' and 'init_cond' in naming -> Done
-TODO: Unify use of 'mesh' and 'grid' in naming -> Done
 TODO: Check sign change in stiffness matrix to accommodate negative wave speed
 TODO: Force input_size for each ANN model to be stencil length
 TODO: Induce shift in IC class