added s few of Roman's E6 custodial symmetry papers to manual,
since that is a really nice alternative formulation of the E6SSM and
can ~fit with our model files since we neglect many couplings.
added FlexibleFuture.txt to doc directory.  Contains updated list of (possible)
future extensions, collaborations, fixes, applications.
Added for others to extend  if they have ideas before we discuss this
after the dust has settled on first FlexibleSUISYDproject.