Merged with latest develop.

b_asic/__init__.py

b_asic/abstract_graph_component.py

b_asic/abstract_operation.py

b_asic/core_operations.py

b_asic/graph_component.py

b_asic/operation.py

b_asic/port.py

b_asic/signal.py

b_asic/signal_flow_graph.py

b_asic/traverse_tree.py

b_asic/utilities.py

test/conftest.py

test/fixtures/operation_tree.py

test/signal_flow_graph/test_signal_flow_graph.py

test/traverse/test_traverse_tree.py