Apiron

Removed
- The `check_for_trailing_slash` argument and default behavior has been removed

Changed
- Service domains and endpoint paths were previously joined per [IETF RCF 1808](https://tools.ietf.org/html/rfc1808.html),
which has surprising edge cases.
These are now always joined by appending the endpoint path;
the previous behavior can be achieved with multiple services or endpoints as needed.

Added
- Exposed ability to explicitly set the response encoding
- Expose pass-through `auth` argument to `requests`

Changed
- Moved all tests to a top-level `tests` package and switched to using the `pytest` runner
- Added missing parameter in docstring for `apiron.client.ServiceCaller.call`
- Removed unused imports from `apiron.client`

Added
- Initial open source release of this package!
- Documentation on use and development of this package
- Code of conduct, contribution guide, and issue templates for contributors