[setup.py] use bump2version, with annotated tags support
[setup.py] use bump2version, with annotated tags support

The original bumpversion is no longer maintained, this is the new blessed fork

https://github.com/peritus/bumpversion/pull/58#issuecomment-289579102
https://github.com/c4urself/bump2version
https://pypi.python.org/pypi/bump2version/0.5.5

Annotated tags, e.g. `git tag -am "blah blah"`, can have a message, record
the date and the name of the tagger, and work with git `describe`.

moyogo/ufo2ft,jamesgk/ufo2fdk,googlefonts/ufo2ft,googlei18n/ufo2ft,jamesgk/ufo2ft