_build_event: Ensure `__name__` is a `str`
_build_event: Ensure `__name__` is a `str`

Python 3 is happy to receive `__name__` objects as Unicode or plain
strings, but Python 2 is not.  This bug shows itself when
`unicode_literals` is imported from calling code.

https://github.com/mriehl/fysom/issues/31

mriehl/fysom