Parallelisation framework

Until now parallelization is done at thrre different level:

1. phasertng C++ threads: configurable with phil parameters
2. Python threads: to make indipendent Janeway monitor, strategy graph and GUI
3. Multiprocessing processes: to really execute in parallel actions in parallel

We should have a global parameter to override the default number of cores that Voyager can use

We can integrate more parallelization frameworks such as grids. Although more complex.