Update README documentation to outline the Vert.x PHP testing framework.
Update README documentation to outline the Vert.x PHP testing framework.

alwinmark/vertx-php,vert-x/mod-lang-php,vert-x/mod-lang-php,khasinski/mod-lang-php,khasinski/mod-lang-php,alwinmark/vertx-php,khasinski/mod-lang-php