Date timezone performance/cleanup [PATCH]

https://bugs.php.net/bug.php?id=63941 Per discussion with Nuno Lopes and Christopher Jones, I have created another patch to simplify guess_timezone() in ext/date/php_date.c Internals summary: removes the newly patched in int value that caches whether a timezone was previously checked or not, as well as reduces complexity by only using timezone for the stored (and checked) timezone value. default_timezone is still used locally for ini_set() calls, but is copied to timezone when checked as valid. Does give a slight performance increase due to less compiled ops. If anyone has any feedback, let me know. Thanks in advance!