Add OSX path discovery for Arduino home, avrdude.
[WIP] Add first draft of array arguments...

Add first draft for handling array arguments to `Node` methods.

__NB__ There seems to be a bug in `nanopb`.

    >>> data = range(5, 0, -1)
    >>> data
    [5, 4, 3, 2, 1]
    >>> [node.array_test(array=data, index=i) for i, d in enumerate(data)]
    [5, 4, 3, 2, 1]
    >>> data = range(5)
    >>> data
    [0, 1, 2, 3, 4]
    >>> [node.array_test(array=data, index=i) for i, d in enumerate(data)]
    [0, 0, 0, 0, 0]

The last response should be `[0, 1, 2, 3, 4]`, not `[0, 0, 0, 0, 0]`.