Add logger examples to getInfo() method

[bonny]

Add an 'examples' key to the array returned by getInfo() for each logger. This information can be used to generate documentation on simple-history.com.

Example from SimpleUserLogger:

	'examples' => array(
		array(
			'description' => 'User fails to login',
			'message' => 'user_login_failed',
			'context' => array(
				'login' => '[email protected]',
			),
		),