Fix php docs and coding style

In this pull request:
+ Add example with MetaEvent function (thank you implement this function)
+ Fix php docs and conding style for source and example
+ Fix NOTICE in `Thruway\Procedure` class
     
            if ($registration->getCurrentCallCount() < $bestRegistration) {
                $bestRegistration = $registration;
            }

to 

           if ($registration->getCurrentCallCount() < $bestRegistration->getCurrentCallCount()) {
                $bestRegistration = $registration;
            }