Simplifications. requests can actually convert the JSON too, but
__parseJSON actually does a lot more than that, so it would require
some substantial refactoring
Remove unnecessary line
Fix variable name
Support for file uploads
Migrate wikifile to Python3
* Remove deprecated getHistory()
* Align getUsage with getAllMembers from Category
  - Remove caching of results
  - Use queryGen
* Use requests for downloading
* Verified uploading works
* Add watchlist option to upload()