inform nuclidemodels about components? maybe undo this.
carpool time.
extraction/inner_bc update procedure compiles. untested.
Merge branch 'develop' into deg_base_case
material moves between DegRateNuclide models.
check if source term is greater than zero before absorbing.
adds zero check to update_inner_bc function for other nuclide models.
Further addresses issue #21. Full deg-rate base case with CORRECT output is now available.