chore(py3): remove outdated compatibility imports

Author: Rotzbua

exhale/configs.py

@@ -51,12 +51,7 @@
 from sphinx.util import logging
 from types import FunctionType, ModuleType
 
-try:
-    # Python 2 StringIO
-    from cStringIO import StringIO
-except ImportError:
-    # Python 3 StringIO
-    from io import StringIO
+from io import StringIO
 
 
 logger = logging.getLogger(__name__)

exhale/graph.py

@@ -23,13 +23,7 @@
 import textwrap
 
 from bs4 import BeautifulSoup
-
-try:
-    # Python 2 StringIO
-    from cStringIO import StringIO
-except ImportError:
-    # Python 3 StringIO
-    from io import StringIO
+from io import StringIO
 
 __all__       = ["ExhaleRoot", "ExhaleNode"]