Add Exception when JSON Serializing Binary Data

Since I can't think of a good way to deal with this, let's just give a
nice error message to point people in the right direction.

Closes #51
remove failing test since I'm not going to fix this use case
pep8
clean up readme whitespace
Add Logging

This helps to figure out which matcher has decided your two cassettes
differ, and figure out when your cassettes have hit the network.

Closes #34
start at filtering out query strings and headers
fix string encoding for base64
pep8
simplify filter implementation and add unit tests
don't mutate request object
filter before serializing and before matching
querystring test doesnt need to match on headers
refactor response retrieval from cassette
lets try this method of filtering requests
add some documentation on the filter api
add filter to changelog