Add relevant bancor v3 tokens to the combos and flashloan tokens

[NIXBNT]

Solves #427

[barakman]

Argument of type 'NoneType' is not iterable, so you probably want to remove that None default value for this list everywhere in the code (or by the least, change it to [], though if no default value is really required, then no need to declare one).

[barakman]

Several tests are failing:

1. fastlane_bot/tests/nbtest/test_900_OptimizerDetailedSlow.py::test_general_and_specific_tests - AssertionError: assert 'amtout must be negative [49.024647265676]' is None

2. fastlane_bot/tests/test_042_TestBancorV3ModeTwoHop.py::test_test_combos - AssertionError: [test_bancor_v3_two_hop] Different data used for tests, expected ***22 combos

3. fastlane_bot/tests/test_05***_BalancerFlashloans.py::test_test_extract_flashloan_tokens - TypeError: argument of type 'NoneType' is not iterable

4. fastlane_bot/tests/test_06***_TestWETHConversion.py::test_wrap_unwrap_original - TypeError: argument of type 'NoneType' is not iterable

Failure 1 is a known issue in general, all the other failures are probably directly related to the changes applied in this PR.