Generic interface to use translate events as API callbacks

The interface declaration regarding parameters that are passed in the callback can change any time. This should be noted in the documentation. In addition it should be noted, that for customers with support contract we take care for their use cases.

implementation idea

The idea is to have a event to external script configuration. The location of the config (ini / DB) is not defined yet.
In the config we could have the following:
ExternalEventHandler.PHP_CLASS_NAME.PHP_EVENT_NAME = URL handler key.
If one of the configured events is triggered the given URL is called.
To avoid network traffic if the handler is on the same machine, an absolute path can be provided instead of an URL. Then the given php script is included instead of called by URL. The paramters are also given in the _POST array in the same way as it would when called by http.

Parameters to the URL handler must be class and event name, and the parameters given to the event itself in php. Wildcards should be also possible! Classname and eventname can be given as string parameter to the handler URL, other parameters should be given as JSON.