Feature/php 7.3

What I did

• Updated Zon core to PHP7.3 compatability
• updated phpunit to version 8

Note

• taken from the current zon branch for pulse

Migration Notes

• FileMaker Library has been removed (https://github.com/msyk/FMDataAPI / https://github.com/airmoi/FileMaker )
• Curl library is no longer in use - use Guzzle rather (http://docs.guzzlephp.org/en/stable/quickstart.html)