Improve api.Category

* Load pages by default
* Add __contains__, __len__
Merge branch 'master' into api
Check for colorama on Windows
doc
Merge branch 'master' into api: api.Category updates
Fix Python compatibility issues with querystring encoding and decoding (Python 2 & 3)

Notably, saving pages with unicode characters now works again in Python 2
Merge branch 'master' into argparse
Allow arguments to be accessed with __getitem__
Basic debugging mode