Fixed merge for develop

b_asic/core_operations.py

b_asic/operation.py

b_asic/signal_flow_graph.py

test/fixtures/port.py

test/fixtures/signal_flow_graph.py

test/test_depends.py

test/test_inputport.py

test/test_outputport.py

test/test_print_sfg.py

test/test_sfg.py

test/test_signal.py

test/test_simulation.py