Switch http mocking library from httpretty to responses
Add initial youtube plugin, with broken tests
Merge pull request #75 from LordAro/responses

Switch http mocking library from httpretty to responses
Fix up tests
Make the formatted string a class variable, document some more
Merge pull request #76 from LordAro/youtub

Youtube plugin [skip ci]
Enable youtube plugin
Fixes to python bitshifting issues, and also increase the exponent limit