Logger Requirements


* logger class, "named" singletons through a factory
* generate unique ID for each script run: 
	isset($_SERVER['UNIQUE_ID'] ? $_SERVER['UNIQUE_ID'] : uniqid('')
	(from realurl)
* logger API
	->flush()
	->log()
* multiple log writers ->addWriter() __construct($writer): 
	DB (default)
	Stream (File, StdErr, StdOut)
	Syslog
	Firebug
	Apache Chainsaw compatible
* filters:
	* for the complete log
	* for individual writers
* support for observers
	$logger = Logger::factory();
	$observer = new Observer();
	$logger->attach($observer);
	$logger->detach($observer);
* multiple log severities: 
	* just go with BSD syslog style? http://tools.ietf.org/html/rfc3164
	* used by ZF, PEAR, sf, F3
* shortcut methods for log severities:
	->notice()
	->info()
	->ok()
	->warning()
	->error()
* parameters for log method:
	package (ExtKey.Component.SubComponent.SubSubComponent...)
	message
	code
	severity
	data
* automatically collected data:
	unique ID per script run, see above
	timestamp including milliseconds
	call trace
	page ID
	BE user
	FE user
* Backend module with list and single view of log entries
	* grouping of multiple events of same type, see Zend screenshot
	* list view: http://framework.zend.com/images/manual/d481d625821a97b9a5eb2cec99dca50e-zend.log.writers.zendmonitor-events.png
	* single view: http://framework.zend.com/images/manual/d481d625821a97b9a5eb2cec99dca50e-zend.log.writers.zendmonitor-event.png