PointIntegralSolver missing default_parameters

[Åshild Telle]

When trying to run this version for python, using code originally written for the 2017.2 version, I got the error

AttributeError: type object 'PointIntegralSolver' has no attribute 'default_parameters'

coming from the line

params.add(PointIntegralSolver.default_parameters())

It seems like this was a part of the 2017 version (https://fenicsproject.org/docs/dolfin/2017.2.0/python/programmers-reference/cpp/fem/PointIntegralSolver.html#dolfin.cpp.fem.PointIntegralSolver) but missing in 2018.1 (https://fenicsproject.org/docs/dolfin/2018.1.0/python/_autogenerated/dolfin.cpp.multistage.html).