Dynare++: improvements to comments

dynare++/integ/cc/precalc_quadrature.hh

dynare++/integ/cc/product.cc

dynare++/integ/cc/product.hh

dynare++/integ/cc/quadrature.hh

dynare++/integ/cc/quasi_mcarlo.cc

dynare++/integ/cc/quasi_mcarlo.hh

dynare++/integ/cc/smolyak.cc

dynare++/integ/cc/smolyak.hh

dynare++/integ/cc/vector_function.cc

dynare++/integ/cc/vector_function.hh

dynare++/integ/src/quadrature-points.cc

dynare++/integ/testing/tests.cc

dynare++/src/dynare3.cc

dynare++/src/dynare3.hh

dynare++/src/dynare_atoms.hh

dynare++/src/dynare_model.cc

dynare++/src/dynare_model.hh

dynare++/src/dynare_params.hh

dynare++/src/forw_subst_builder.cc

dynare++/src/forw_subst_builder.hh