Major overhaul of VhAtMin() in nmssmsoftsusy.cpp to take into account different
scenarios of vanishing vevs.  Tested against CHECKMIN() routine
of NmssmTools.  Code compiles and produces empty diff against SLHA2
inputs from commit 7bd3...
Moved call to VhAtMin() from end of rewsb() to end of lowOrg().  Called at SUSY
scale, just before run down to MZ.  Empty diffs against commit
7bd3...
Changed VhAtMin() to now take soft masses mHu2, mHd2, mSsq as inputs.  Makes
more sense for EWSB requirements on potentials V1 and V2