event filters

[sctt]

when i process events, i need to filter them based on specific event data.
i could use predicates as closures, but that solution is too hard and complex, especially if filters have to be dynamic.
i recommend closures if you really have to filter with some particular criteria, but if you just need to filter evaluating event data, i don't think they are the optimal solution.

that's why i added the capability of specifying an array of filters during event registration.
filters are specified as regular expressions.
here's an example:

$client->registerEventListener(
    function($event) {var_dump($event);},
    array(
        'event' => '/Hangup/',
        'channel' => '/Local\/27.*/',
   )
);

i did some test with a couple of events and filters, and it actually seems to work.

let me know what you think, i will write a unit test only if you like this.