Revert "Deleted README.md"

setup.py

src/main.cpp

test/__init__.py

test/conftest.py

test/fixtures/operation_tree.py

test/fixtures/port.py

test/fixtures/signal.py

test/operation/test_abstract_operation.py

test/test_core_operations.py

test/test_graph_id_generator.py

test/test_inputport.py

test/test_operation.py

test/test_outputport.py

test/test_signal.py