Upgrade phpunit config

See merge request !6

Declare coworker context as part of env

See merge request !8

General composer update

See merge request !5

* Fix conflict with CMS PharInterceptors. Preload key PHP files before CMS loads.
* Change `*BUILTIN*` to `MINIPIPE`. Allow negotiation flags.
* Update docs

Cleanup option names

See merge request !4