allow ADL of `toString` in Property
This is needed to be consistent with the ADL of toStream
and parse
.
Also, add dedicated toString
to GaudiMath::Interpolation. Required
to make sure that toStream
generates valid python (i.e. it must include
quotes) and toString
can be parsed back by fromString
(i.e. it must
not include the quotes!)
Edited by Gerhard Raven