Add support for listing annotator configs

This merge request adds several features:

• Add support for listing annotator configs
• Account for unicode in Python 2
• Replace database directories in bob bio annotate command
• Fixed a bug in FailSafe annotator where the annotations could be None

bob/bio/base/annotator/FailSafe.py

@@ -38,7 +38,7 @@ class FailSafe(Annotator):
             if not annotations:
                 logger.debug(
                     "Annotator `%s' returned empty annotations.", annotator)
-            kwargs['annotations'].update(annotations)
+            kwargs['annotations'].update(annotations or {})
             # check if we have all the required annotations
             if all(key in kwargs['annotations'] for key in self.required_keys):
                 break