setup.cfg: add versioneer and bumpversion configurations

I had to remove the comments because bumpversion will strip them out anyway upon re-writing the updated version string in setup.cfg file.
Similarly, I had to normalize the whitespace like bumpversion would do. :-/

`tag=True` option means a tag is automatically created when bumping the version with bumpversion script.
However, in order to get 'annotated' instead of 'lightweight' tags -- i.e. the tag also contains the tag author, date and message --, we need to (temporarily?) use a fork of bumpversion that includes an unmerged PR: https://github.com/peritus/bumpversion/pull/58

setup.cfg

@@ -1,3 +1,10 @@
+[bumpversion]
+current_version = 3.1.2
+commit = True
+tag = True
+tag_name = {new_version}
+files = Lib/fontTools/__init__.py
+
 [wheel]
 universal = 1
 
@@ -9,19 +16,23 @@ test = pytest
 
 [tool:pytest]
 minversion = 2.8
-testpaths =
-    Lib/fontTools
-python_files =
-    *_test.py
-python_classes =
-    *Test
-addopts =
-    # run py.test in verbose mode
-    -v
-    # show extra test summary info
-    -r a
-    # run doctests in all .py modules
-    --doctest-modules
-    # py.test raises ImportError with inspect.py (requires pygtk) and with
-    # reportLabPen.py (reportlab). They don't have doctests, it's OK to skip.
-    --doctest-ignore-import-errors
+testpaths = 
+	Lib/fontTools
+python_files = 
+	*_test.py
+python_classes = 
+	*Test
+addopts = 
+	-v
+	-r a
+	--doctest-modules
+	--doctest-ignore-import-errors
+
+[versioneer]
+VCS = git
+style = pep440
+versionfile_source = Lib/fontTools/_version.py
+versionfile_build = fontTools/_version.py
+tag_prefix = 
+parentdir_prefix = fonttools-
+