* Adds STARTTLS support
* Adds TLSMode enum to support various tls and unencrypted modes. Change default SMTP init to require STARTTLS and port 587
* Improve comments and names
* fix tests
* fix tests, update readme/migration, regen jazzy
* add tests to LinuxMain
* update bluecryptor to 1.0.2. add swift 4.1 support
* loosen spm versioning
* linux swift build failure
* linux
* linux
* linux
* linux
* update docs and regen jazzy