use make -j all in dunepy at startup
Problem
If a header like fvector.hh
changes all python JIT compiled modules have to be recompiled. At the moment that is done during the import, i.e., sequentially which can be time consuming.
Solution
During the first import of ``dune.generatorrun make in parallel on all existing modules. Possible approach would be to add all targets to
all` in `CMakeList.txt` in dune-py and then run `make -jN all` with some suitable choice of `N`.