Lenddo

Changes
- Add proxy support

This release will add support for `python 3` while maintaining compatibility with `python 2`.

Changes
- Add support for `python 3`
- Add new module `lenddo_api_client.errors` for exception handling. This is just a wrapper with the builtin `HTTPError` and `URLError`

Misc
- Update documentation in `README.md` to reflect above changes

No significant change were made, this release is a structure change to enable the package upload to pypi.

Changes
- Restructure files to enable installation through pypi and setup.py.