Need more extreme directions for continuous variables to be robust
with bounded kernels - uniform spreading directions too, well,
uniformly. Added chidev/gasdev rng and replaced ran3(&seed) with
chidev(&seed,3) and it appears this is a more robust choice. Also
reverted lbc and hbc to 0.5 and 1.5 - note they are used to `center'
the chisquare random deviates and also enforce a lower bound. But
there is no strict upper bound anymore.