allowing nested parallelism in python multiprocessing

Right now the use of an archipelago with, for example, a bfe based algo will not work if python multiprocessing islands are used with a multiprocessing bfe. The reason is that daemonic processes do not allow nested parallelism.
```python
AssertionError: daemonic processes are not allowed to have children
```

A possible solution would be the use of non daemonic processes in the python mp module.

See related discussions:
https://stackoverflow.com/questions/28491558/launching-nested-processes-in-multiprocessing
https://stackoverflow.com/questions/6974695/python-process-pool-non-daemonic