Version 5.2.15 (May 10th 2016)

Version 5.2.15 (May 10th 2016)

- Added ability to inject custom address validators, and set the default validator
- Fix TLS 1.2 compatibility
- Remove some excess line breaks in MIME structure
- Updated Polish, Russian, Brazilian Portuguese, Georgian translations
- More DRY!
- Improve error messages
- Update dependencies
- Add example showing how to handle multiple form file uploads
- Improve SMTP example
- Improve Windows compatibility
- Use consistent names for temp files
- Fix gmail XOAUTH2 scope, thanks to @sherryl4george
- Fix extra line break in getSentMIMEMessage()
- Improve DKIM signing to use SHA-2