Various simplifications

src/ComputingTasks.cc

src/ComputingTasks.hh

src/DynamicModel.cc

src/DynamicModel.hh

src/ExprNode.cc

src/ExprNode.hh

src/ExternalFunctionsTable.hh

src/ModFile.cc

src/ModelEquationBlock.cc

src/ModelTree.cc

src/NumericalConstants.cc

src/NumericalInitialization.cc

src/ParsingDriver.cc

src/Shocks.cc

src/Shocks.hh

src/StaticModel.cc

src/SubModel.cc

src/SymbolList.cc

src/SymbolList.hh

src/SymbolTable.cc