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

The original bumpversion is no longer maintained, this is the new blessed fork

peritus/bumpversion#58 (comment)
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`.

setup.py

@@ -41,7 +41,7 @@ def bumpversion(self, part, tag=False, message=None):
 
         args = (
             (['--verbose'] if self.verbose > 1 else []) +
-            (['--tag'] if tag else ['--no-tag']) +
+            (['--tag', '--tag-message', message] if tag else ['--no-tag']) +
             (['--message', message] if message is not None else []) +
             [part]
         )
@@ -153,7 +153,7 @@ def run(self):
     include_package_data=True,
     license="MIT",
     setup_requires=pytest_runner + wheel + (
-        ['bumpversion'] if {'release', 'bump_version'}.intersection(sys.argv) else []),
+        ['bump2version'] if {'release', 'bump_version'}.intersection(sys.argv) else []),
     tests_require=[
         'pytest>=2.8',
     ],