Add lib2to3 fixer base code

Switching to using RedBaron instead of lib2to3, committing to save lib2to3 code in case using Baron is not successful.

scripts/fix_ext_import.py

@@ -0,0 +1,20 @@
+from lib2to3.fixer_base import BaseFix
+from lib2to3.fixer_util import Name, syms
+
+
+class FixExtImport(BaseFix):
+
+    PATTERN = "fixnode='oldname'"
+
+    def transform(self, node, results):
+        fixnode = results['fixnode']
+        fixnode.replace(Name('newname', prefix=fixnode.prefix))
+
+        if node.type == syms.import_from and \
+                getattr(results['imp'], 'value', None) == 'flask.ext':
+            return 0
+            # TODO: Case 2
+
+
+# CASE 1 - from flask.ext.foo import bam --> from flask_foo import bam
+# CASE 2 - from flask.ext import foo --> import flask_foo as foo