BUG: argument check in LBFGSB too restrictive

This is in response to
https://issues.itk.org/jira/browse/ITK-3014

The authors of the algorithm and the fortran
code that ITK uses specify in thir example driver
that one of CostFunctionConvergenceFactor
and ProjectedGradientTolerance can be zero
but not both.

Change-Id: Ia5b1afd15f97e1c50cd5f46b543a174e1a25691a
Merge topic 'LBFGSBCostFunctionParameter'

d9b623d BUG: argument check in LBFGSB too restrictive