Load Old Cassettes

Add backwards-compatible cassette loading code that can load
the old style header dicts from response cassettes.

vcr/__init__.py

@@ -3,6 +3,5 @@ from config import VCR
 default_vcr = VCR()
 
 
-# Also, make a 'load' function available
 def use_cassette(path, **kwargs):
     return default_vcr.use_cassette(path, **kwargs)