Fixed functions that return arrays and functions that deal with FANN::connection arrays

The two member functions `get_layers_array` and `get_bias_array` expected a Python list as an output argument. This has been modified so that they now return lists directly, making the interface a lot more reasonable for Python programmers.

Additionally, the member functions `get_connection_array` and `set_weights_array` could not be used since there was no SWIG interface for arrays of `FANN::connection` structs.
This interface as been added; and, on the side, the signature of `get_connection_array` has been modified as described above.
For reference: `set_weights_array` now expects a list of tuples `(from_neuron, to_neuron, weight)`, whereas `get_connection_array` returns a list of such tuples.

Running these functions on my computer didn't reveal any memory leaks.
Still, my lack of knowledge in C and C++ programming might advise to carefully check my additions.