createTestPlan "note" should be "notes"

[nck974]

I think there is a mistake here: https://github.com/lczub/TestLink-API-Python-client/blob/master/src/testlink/testlinkapigeneric.py#L677

It should say notes instead of note. After passing that parameter to the function it works, otherwise it does not complain but does not add the notes in testlink.