Feature/randomness

[drodarie]

• Add randomness to NEST simulations (seed)
• Allow NEST random distribution for neuron parameters

close #6

[drodarie]

Hmm for some reason the hasattr you suggested does not work.
To give some context, I copied the implementation of Distribution in _distributions.py in bsb.core, and here too the __getattr__ uses self.__dict__.
I will revert the change and put a comment but I am not sure why this happens

[Helveg]

ah oops, I did not see that this was inside of __getattr__. It doesn't work because hasattr uses the entire Python attribute access cascade, including a lookup of __getattr__ itself :)

[Helveg]

I'll approve it, but once bsb-core implements reproducibility/randomness systematically, this logic will probably have to be redone.