Zdesk

- Switch from `httplib2` to `requests`
- Add `files` parameter to support multipart uploads for Help Center attachment
style requests
- Enhance `api_gen.py` to handle downloading and patching of developer.zendesk.com
- Add Zopim and numerous other API endpoints
- Regenerate API from updated mirror. See [full
commit](https://github.com/fprimex/zdesk/commit/d679a734292de5ade82cb4d4533e79368510769d)

- Remove `common_params`, allowing all kwargs to be passed as queries

- Add exception classes to top level. e.g. `from zdesk import ZendeskError` works now
- Modify `api_gen.py` so that `update_many_update` becomes just `update_many`
- Regenerate API from updated mirror. See [full
commit](https://github.com/fprimex/zdesk/commit/8a6bac52a912ce45c3a47911331b381cf963abc1)

- Remove explicit HTTP status code checking. Success is always in the 200
range, with some specific exceptions raised for only a few specific 400 range
codes.

- Support non-JSON data for, e.g., creating uploads
- Add `sort_by` common parameter
- Regenerate API from updated mirror. See [full
commit](https://github.com/fprimex/zdesk/commit/cbeb1ecd0ae4580caa3ad434c74e7e49d4378c19)
- Update `examples/__init__.py` with fixes and ticket updates and uploads
- Reorder CHANGELOG.md with most recent releases at top

- Add `get_all_pages` option to call to exhaustively follow `next_page`
- Combine and reduce multiple requests when using `get_all_pages`