event names are required to be lowercase. This was the issue in bug #12, fixes issue #12.
php_exporter has been modified to  check if it matches when a regeex is used with uppercase letters as well. If that matches, it adds a error and after that still adds the event to the list. No logicException is thrown when this happens.
Also added testcases to check for uppercase and lowercase event names for tests.
Thanks @rxu for reporting.