Updated driver_structure.hpp for harmonic balance preconditioning
Updated driver_structure.hpp for harmonic balance preconditioning

SetHarmonicBalance() added to CHB_Driver to prepare code to precondition harmonic balance source term using approach from Thomas et al. in AIAA 2009-4270.
hlkline/SU2,drewkett/SU2,drewkett/SU2,hlkline/SU2,drewkett/SU2,srange/SU2,srange/SU2,srange/SU2,hlkline/SU2,hlkline/SU2,srange/SU2,drewkett/SU2,hlkline/SU2,drewkett/SU2