(up until now the evaluator was passed in)

improve test a bit - also see if a reference to a FV and an existing
GF can be used

improve the implementation of the gridFunction
Also remove some deprecated functionality

remove some codes that not needed anymore

dune-function.py -> dune-function.notworking (needs to be adapted to new dune-functions interface)
also made some tests work with newer API

some bug fixes with correct C++ type export for grid functions from C++ lambda

improve handling of grid functions

minor fixes

some more minor improvements (make it easy to use io.StringIO also with algorithm)

export a template argument

[bugfix][numydatahandle] fix forward declaration of MCMGMapper.

improve usage of grid function where user can provide a lambda of the form
[x=arg0,y=arg1](e,x) {...};
instead of
auto f(x,y) { return [x,y](e,x) {...}; }

improve determining the dimension of the return value of grid functions
and make sure that fieldvectors of the right side are registered