Update subliminal to 2.0.5

Also updates:
- appdirs-1.4.3
- babelfish-0.5.5
- beautifulsoup4-4.6.3
- certifi-2018.11.29
- chardet-3.0.4
- click-7.0
- decorator-4.3.0
- dogpile.cache-0.7.1
- enzyme-0.4.1
- guessit-3.0.3
- idna-2.8
- pbr-5.1.1
- pysrt-1.1.1
- python-dateutil-2.7.5
- pytz-2018.7
- rarfile-3.0
- rebulk-1.0.0
- requests-2.21.0
- six-1.12.0
- stevedore-1.30.0
- urllib3-1.24.1

libs/stevedore/example/base.py

@@ -0,0 +1,22 @@
+import abc
+
+import six
+
+
+@six.add_metaclass(abc.ABCMeta)
+class FormatterBase(object):
+    """Base class for example plugin used in the tutorial.
+    """
+
+    def __init__(self, max_width=60):
+        self.max_width = max_width
+
+    @abc.abstractmethod
+    def format(self, data):
+        """Format the data and return unicode text.
+
+        :param data: A dictionary with string keys and simple types as
+                     values.
+        :type data: dict(str:?)
+        :returns: Iterable producing the formatted text.
+        """