Added Tout and Pringle 1992 magnetic wind loss with multiplier option (default...

Added Tout and Pringle 1992 magnetic wind loss with multiplier option (default is 0.0, so this wind is off)

now propagate vb flag through nuclear-burning routines

change to stellar structure to only allow thermal pulses if Mc < MCh: this *might* help mint post-CHeB (although the timescales are still all messed up!)