Use isinstance instead of obj.__bases__

This is a small change but will enable much easier extending of
auto-sklearn algorithms, since without this change, all classes
are expected to directly inherit from AutoSklearn base calsses,
and do not allow additional layers of inheritance.

autosklearn/pipeline/components/base.py

@@ -43,7 +43,7 @@ def __init__(self, base_class):
         self.components = OrderedDict()
 
     def add_component(self, obj):
-        if inspect.isclass(obj) and self.base_class in obj.__bases__:
+        if inspect.isclass(obj) and isinstance(obj, self.base_class):
             name = obj.__name__
             classifier = obj
         else: